Suppose $$\frac{2(1-2x)}{x^2-x-2} = \frac{A}{x-2} + \frac{B}{x+1}$$
How can I get the value of $A+B$ for my math exam?
Suppose $$\frac{2(1-2x)}{x^2-x-2} = \frac{A}{x-2} + \frac{B}{x+1}$$
How can I get the value of $A+B$ for my math exam?
This should help. $$ 2 - 4x = Ax + A + Bx - 2B = (A+B) x + (A-2B)$$
Compare coefficients.