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Solution of the inequality 2x+34x−5≥0\frac{2x+3}{4x-5} \geq 0 is

Solution

✅ Correct Option: 4

The fraction 2x+34x−5\frac{2x+3}{4x-5} is positive or zero when both numerator and denominator have the same sign, or when the numerator is zero. The denominator cannot be zero.


Finding where the numerator equals zero:

2x+3=02x + 3 = 0

x=−32x = -\frac{3}{2}

Finding where the denominator equals zero:

4x−5=04x - 5 = 0

x=54x = \frac{5}{4}

These critical points divide the number line into three regions.


Testing the region x<−32x < -\frac{3}{2} using x=−2x = -2:

Numerator: 2(−2)+3=−12(-2) + 3 = -1 (negative)

Denominator: 4(−2)−5=−134(-2) - 5 = -13 (negative)

Fraction: (−)(−)=(+)\frac{(-)}{(-)} = (+) ✓


Testing the region −32<x<54-\frac{3}{2} < x < \frac{5}{4} using x=0x = 0:

Numerator: 2(0)+3=32(0) + 3 = 3 (positive)

Denominator: 4(0)−5=−54(0) - 5 = -5 (negative)

Fraction: (+)(−)=(−)\frac{(+)}{(-)} = (-) ✗


Testing the region x>54x > \frac{5}{4} using x=2x = 2:

Numerator: 2(2)+3=72(2) + 3 = 7 (positive)

Denominator: 4(2)−5=34(2) - 5 = 3 (positive)

Fraction: (+)(+)=(+)\frac{(+)}{(+)} = (+) ✓


At x=−32x = -\frac{3}{2}:

2(−32)+34(−32)−5=0−11=0\frac{2(-\frac{3}{2})+3}{4(-\frac{3}{2})-5} = \frac{0}{-11} = 0

Since 0≥00 \geq 0, this point is included.

At x=54x = \frac{5}{4}:

The denominator is zero, so this point is excluded.


The solution is (−∞,−32]∪(54,∞)\left(-\infty, -\frac{3}{2}\right] \cup \left(\frac{5}{4}, \infty\right)

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