If $\frac{5x + 4}{(x + 2)(x - 1)} = \frac{A}{x + 2} + \frac{B}{x - 1}$, what is $A$?

Explanation

1. 01

   Multiply through: $5x + 4 = A(x - 1) + B(x + 2)$.

2. 02

   Put $x = -2$: $-6 = -3A$, so $A = 2$. (And $x = 1$ gives $B = 3$.)