Inequality LEVEL- 1
Q1–10 of 50Solve the following inequality :
3x² – 7x + 4 ≤ 0
Step 1: Factor the quadratic expression:
Step 2: The roots are $x = 1$ and $x = \frac{4}{3}$. Since it is $\le 0$, the solution lies between the roots:
Solve the following inequality:
3x² – 7x – 6 < 0
Step 1: Factor the quadratic expression:
Step 2: The critical values are $x = -\frac{2}{3} \approx -0.666...$ and $x = 3$.
Step 3: For the inequality to be negative, $x$ must lie between the roots:
Solve the following inequality :
3x² – 7x + 6 < 0
Step 1: Calculate the discriminant $D = b^2 - 4ac$:
Step 2: Since $D < 0$ and the leading coefficient $a = 3 > 0$, the quadratic expression is positive for all real $x$. Therefore, $3x^2 - 7x + 6$ can never be less than zero.
Solve the following inequality :
x² – 3x + 5 > 0
Step 1: Calculate the discriminant:
Step 2: Since $D < 0$ and $a = 1 > 0$, the parabola opens upwards and never crosses the x-axis. Thus, the expression is always positive for all real $x$.
Solve the following inequality :
x² – 14x – 15 > 0
Step 1: Factor the expression:
Step 2: The roots are $x = -1$ and $x = 15$. For the product to be positive, $x$ must lie outside the roots:
Solve the following inequality :
2 – x – x² ≥ 0
Step 1: Multiply the inequality by $-1$ (and flip the inequality sign):
Step 2: Factor:
Step 3: The roots are $x = -2$ and $x = 1$. The solution is:
Solve the following inequality :
|x² – 4x| < 5
Step 1: Split into double inequalities: $-5 < x^2 - 4x < 5$.
Part A: $x^2 - 4x > -5 \implies x^2 - 4x + 5 > 0$.
Discriminant $D = 16 - 20 = -4 < 0$. Holds true for all real $x$.
Part B: $x^2 - 4x < 5 \implies x^2 - 4x - 5 < 0 \implies (x - 5)(x + 1) < 0$.
Solution: $-1 < x < 5$.
Answer: (d) –1 < x < 5
Solve the following inequality :
|x² + x| – 5 < 0
Step 1: Rearrange to $\vert{}x^2 + x\vert{} < 5 \implies -5 < x^2 + x < 5$.
Part A: $x^2 + x + 5 > 0$ ($D = 1 - 20 < 0$, true for all real $x$).
Part B: $x^2 + x - 5 < 0$.
Roots are $x = \frac{-1 \pm \sqrt{21}}{2}$.
Solution is $\frac{-1 - \sqrt{21}}{2} < x < \frac{-1 + \sqrt{21}}{2}$.
Conclusion: None of the listed options reflect this boundary range.
Solve the following inequality :
|x² – 5x| < 6
Step 1: Double inequality: $-6 < x^2 - 5x < 6$.
Part A: $x^2 - 5x + 6 > 0 \implies (x - 2)(x - 3) > 0 \implies x < 2 \text{ or } x > 3$.
Part B: $x^2 - 5x - 6 < 0 \implies (x - 6)(x + 1) < 0 \implies -1 < x < 6$.
Intersection of Part A and B: $(-1 < x < 2) \cup (3 < x < 6)$
Solve the following inequality :
|x² – 2x| < x
Step 1: Since absolute value is non-negative, $x > 0$.
Step 2: $-x < x^2 - 2x < x$.
Left: $x^2 - x > 0 \implies x(x - 1) > 0$. Since $x > 0$, this requires $x > 1$.
Right: $x^2 - 3x < 0 \implies x(x - 3) < 0$. Since $x > 0$, this requires $x < 3$.
Step 3: Combining yields $1 < x < 3$.