Mark M. answered 05/27/21
Retired math prof. Very extensive Precalculus tutoring experience.
3/(x-1) ≥ 4/(x+2)
3/(x-1) - 4/(x+2) ≥ 0
[3(x+2) - 4(x-1)] / [(x-1)(x+2)] ≥ 0
(10-x) / [(x-1)(x+2)] ≥ 0
Numerator = 0 when x = 10 and Denominator = 0 when x = -2 or 1
Divide the number line into a collection of intervals using -2, 1, and 10 as boundaries.
When x < -2, the numerator and denominator are both positive (try x = -3)
When -2<x<1, the numerator and denominator have opposite signs (try x = 0)
When 1<x<10, the numerator and denominator are both positive (try x = 2)
When x>10, the numerator and denominator have opposite signs (try x = 11)
Solution set: (-∞, -2) ∪ (1,10]