Q.37−(3x+5)>9x−8(x−3)
🔒You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.
🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Linear Inequality Solutions
Linear Inequality Solutions – A First Look
Imagine you're standing on a number line. You know exactly where the number 5 is. But what if I asked you to stand on "all numbers greater than 5"? You can't stand on all of them at once — they stretch infinitely to the right. That's the core idea of an inequality: instead of one exact point, you get a whole region of possible values.
A linear inequality is just like a linear equation (ax+b=0), but instead of an equals sign, you have one of these: <, >, ≤, or ≥. The solution is not a single number — it's an interval (or a union of intervals) on the number line.
From Equation to Inequality
Start with a simple equation:
2x+3=7
Solve it: 2x=4⟹x=2. One point.
Now change it to an inequality:
2x+3>7
Solve it the same way — but the meaning changes. Subtract 3: 2x>4. Divide by 2: x>2.
The solution is all numbers greater than 2. On a number line, you draw an open circle at 2 (because 2 itself is not included) and shade everything to the right.
If you multiply or divide both sides of an inequality by a negative number, the inequality sign reverses. For example: −x<5 becomes x>−5. This is the single most common mistake students make.
The Four Types of Solutions
| Inequality | Meaning | Number line representation |
|---|---|---|
| x>a | All numbers strictly greater than a | Open circle at a, shade right |
| x≥a | All numbers greater than or equal to a | Closed (filled) circle at a, shade right |
| x<a | All numbers strictly less than a | Open circle at a, shade left |
| x≤a | All numbers less than or equal to a | Closed circle at a, shade left |
The solution set is usually written in interval notation:
- x>2 → (2,∞)
- x≤−3 → (−∞,−3]
Parentheses ( or ) mean the endpoint is not included. Brackets [ or ] mean it is included.
Solving a Linear Inequality: Step by Step
Solve 3x−5≤7x+3.
-
Bring variable terms to one side:
3x−5−7x≤3
−4x−5≤3
-
Isolate the variable term:
−4x≤8
-
Divide by the coefficient (here it's −4, so reverse the sign):
x≥−2
The solution is x≥−2, or in interval notation: [−2,∞).
Always check your answer by testing a number from the solution set. For x≥−2, test x=0: 3(0)−5=−5 and 7(0)+3=3. Is −5≤3? Yes. Now test a number outside, say x=−3: 3(−3)−5=−14 and 7(−3)+3=−18. Is −14≤−18? No — so the inequality fails, confirming our solution is correct.
Why This Matters …
Concept: Linear Inequality Solutions
We solve by simplifying both sides, collecting like terms, and isolating x.
Step 1. Expand the left side:
37−3x−5>9x−8(x−3)
32−3x>9x−8x+24
Step 2. Simplify the right side:
32−3x>x+24
Step 3. Collect all x terms on one side and constants on the other:
32−24>x+3x …
Simplify both sides by distributing and combining like terms, then isolate x to find that x<2.
Linear inequalities work exactly like equations when you add, subtract, multiply, or divide—with one critical exception: multiplying or dividing by a negative number flips the inequality sign. The strategy is to simplify both sides first, then collect all terms with the variable on one side and constants on the other.
Let's start by expanding and simplifying each side of the inequality.
Left side:
37−(3x+5)=37−3x−5=32−3x
Right side:
9x−8(x−3)=9x−8x+24=x+24
Now the inequality becomes:
32−3x>x+24
With both sides simplified, we can solve for x systematically.
- Move all terms containing x to one side. Subtract x from both sides:
32−3x−x>24
32−4x>24
- Isolate the term with x. Subtract 32 from both sides:
−4x>24−32
−4x>−8
- Solve for x by dividing both sides by −4. …
Showing the 12 most recent of 36 on this concept.
- KEAM 2026Set eng-2026-04174 marksMCQQ.The solution set of the inequality 6(2x+3)+x>53−2x is (A) (37,∞) (B) (−∞,37) (C) (37,2) (D) (−2,37) (E) (−37,∞)
›Reveal solutionSolution
Expand and collect terms: 15x>35, so x>37.
Expand the left side:
6(2x+3)+x=12x+18+x=13x+18.
The inequality becomes …
- KEAM 2026Set eng-2026-04174 marksMCQQ.In a right-angled trapezium ABCD, ∠A=90∘, ∠D=90∘, AB=7a+1, CD=3a+1 and AD=3a. If the perimeter of the trapezium is greater than 56 but less than 92, then the range of possible values of a, is (A) 4<a<211 (B) 27<a<5 (C) 3<a<29 (D) 3<a<7 (E) 3<a<5
›Reveal solutionSolution
The perimeter is 18a+2; solving 56<18a+2<92 gives 3<a<5.
In the right-angled trapezium, AB∥CD with the perpendicular leg AD=3a. The horizontal offset between the parallel sides is AB−CD=(7a+1)−(3a+1)=4a, so the slant side is
BC=(4a)2+(3a)2=25a2=5a.
The perimeter is …
- KEAM 2026Set eng-2026-04184 marksMCQQ.The set of all x satisfying the inequality 8+3x>4(x−3)+2 is (A) (18,∞) (B) (20,∞) (C) (−∞,18) (D) (−∞,20) (E) (−20,18)
›Reveal solutionSolution
Solving 8+3x>4(x−3)+2 yields x<18.
8+3x>4(x−3)+2=4x−12+2=4x−10.
Bring terms together:
8+10>4x−3x⇒18>x. …
- KEAM 2026Set eng-2026-04194 marksMCQQ.Let x be a real number such that 5<∣x−1∣<15. Then (A) −18<x<−3 or 3<x<19 (B) −14<x<−3 or 6<x<17 (C) −16<x<−2 or 6<x<20 (D) −14<x<−4 or 6<x<16 (E) −10<x<−1 or 3<x<18
›Reveal solutionSolution
Solve the two-sided inequality: −14<x<−4 or 6<x<16.
Upper bound ∣x−1∣<15: −15<x−1<15⇒−14<x<16.
Lower bound ∣x−1∣>5: x−1>5 or x−1<−5⇒x>6 or x<−4. …
- KEAM 2026Set eng-2026-04194 marksMCQQ.Let x be a real number such that x−2x−3≥1. Then the solution set of the inequality is (A) (−∞,3) (B) (−∞,2) (C) [0,∞) (D) (−9,∞) (E) (0,8)
›Reveal solutionSolution
Subtract 1 and analyse the sign: solution is (−∞,2).
Rearrange.
x−2x−3−1≥0⇒x−2(x−3)−(x−2)≥0⇒x−2−1≥0. …
- KEAM 2026Set eng-2026-04204 marksMCQQ.If x+22x−10≥x−5 then x lies in (A) (−∞,−1)∪[0,6] (B) (−∞,−2)∪[−1,5] (C) (−∞,−2)∪[0,10] (D) (−∞,0)∪[0,5] (E) (−∞,−2)∪[0,5]
›Reveal solutionSolution
Factoring 2x−10=2(x−5) and moving everything to one side yields −x+2x(x−5)≥0, i.e. x+2x(x−5)≤0. A sign chart gives x<−2 or 0≤x≤5.
Start from x+22x−10≥x−5. Since 2x−10=2(x−5):
x+22(x−5)−(x−5)≥0⇒(x−5)[x+22−1]≥0.
Simplify the bracket:
x+22−(x+2)=x+2−x,
so
(x−5)⋅x+2−x≥0⟺x+2x(x−5)≤0.
Critical points: x=−2 (excluded), x=0, x=5. Sign of x+2x(x−5): …
- KEAM 2026Set eng-2026-04204 marksMCQQ.If 10<∣x+10∣≤25, then x lies in (A) [−45,−20)∪(0,15] (B) [−35,−25)∪(0,15] (C) [−35,−20)∪(0,15] (D) [−35,−20)∪(0,25] (E) [−35,−10)∪(0,15]
›Reveal solutionSolution
Substitute y=x+10. The double inequality 10<∣y∣≤25 means y∈[−25,−10)∪(10,25]. Converting back (x=y−10) gives x∈[−35,−20)∪(0,15].
Let y=x+10, so the condition is 10<∣y∣≤25.
This breaks into:
∣y∣>10⇒y<−10 or y>10,
∣y∣≤25⇒−25≤y≤25. …
- KEAM 2026Set eng-2026-04204 marksMCQQ.A number x is randomly chosen from the set of natural numbers less than or equal to 100. Then the probability of the event that the chosen number satisfies the inequality x−30(x−15)(x−70)≥0, is (A) 0.36 (B) 0.47 (C) 0.48 (D) 0.49 (E) 0.46
›Reveal solutionSolution
Sign-analyse x−30(x−15)(x−70)≥0 over integers 1–100 (x=30 excluded).
Critical points: 15,30,70 (with x=30 making the denominator zero).
- x<15: expression <0.
- 15≤x<30: ≥0 (equals 0 at x=15). Integers 15,…,29 → 15 values.
- 30<x<70: <0. …
- KEAM 2026Set eng-2026-04214 marksMCQQ.If (x−1)(x2−5x+7)<(x−1), then x belongs to (A) (−∞,−1)∪(2,3) (B) (−∞,−1]∪[2,3] (C) (−∞,1)∪(2,3) (D) (−∞,1)∪[2,3) (E) (−∞,1)∪(2,3]
›Reveal solutionSolution
Bringing everything to one side factors as (x−1)(x−2)(x−3)<0, giving (−∞,1)∪(2,3).
(x−1)(x2−5x+7)−(x−1)<0⇒(x−1)(x2−5x+6)<0⇒(x−1)(x−2)(x−3)<0. …
- KEAM 2026Set eng-2026-04214 marksMCQQ.The solution set of x+x1>2 is (A) R (B) R−{0} (C) R−{1,−1} (D) R−{−1} (E) R−{−1,0,1}
›Reveal solutionSolution
By AM–GM ∣x+1/x∣≥2 with equality only at x=±1; excluding those and x=0 gives R−{−1,0,1}.
For real x=0, x+x1≥2, with equality exactly when x=±1. The strict inequality >2 therefore holds for all x except x=±1; al …
- KEAM 2026Set eng-2026-04224 marksMCQQ.If 421x−6−9≤0 and 3x−1+1≥0,x∈R, then x lies in the interval (A) [−2,1] (B) [−2,2] (C) [−1,2] (D) [2,4] (E) [−2,4]
›Reveal solutionSolution
Solve each inequality separately and intersect.
First: 421x−6≤9⇒21x−6≤36⇒21x≤42⇒x≤2. …
- KEAM 2026Set eng-2026-04224 marksMCQQ.If ∣2x−3∣<5,x∈R, then x lies in the interval (A) [−1,1] (B) [−1,4] (C) (−1,4) (D) (−2,4) (E) [−2,4]
›Reveal solutionSolution
Remove the modulus with a two-sided inequality; strict < gives an open interval.
∣2x−3∣<5 means −5<2x−3<5.
Add 3: −2<2x<8. Divide by 2: −1<x<4. …
🎓Unlock everything free for 14 days
- ✓Full step-by-step solutions
- ✓Concept-first explanations
- ✓Methods, shortcuts & mistakes
- ✓PYQ mapping + timed mock tests
Full access for 14 days. No credit card required.