Solving quadratic inequality:12x^2 + 11x ≤ 15

12x^2 + 11x ≤ 15

12x² + 11x ≤ 15
12x² + 11x - 15 ≤ 0
(3x + 5)(4x - 3) ≤ 0

If the product of two factors is negative, then only one factor is negative.

If 3x + 5 ≤ 0,
3x ≤ - 5
x ≤ - 5/3

and

4x - 3 ≥ 0,
4x ≥ 3
x ≥ 3/4

Since the equation is a parabola, x is outside the feasible domain,
which is between the roots, so

3x + 5 ≥ 0,
3x ≥ - 5
x ≥ - 5/3
- 5/3 ≤ x

and

4x - 3 ≤ 0,
4x ≤ 3
x ≤ 3/4

Domain:

- 5/3 ≤ x ≤ 3/4
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