Question

f(x)= $\frac{2x-3}{x+4}$

$f^{l}$(-5) -?

Answer 1

f'= ((2x-3)'(x+4)-(2x-3)(x+4)')/(x+4)²= (2(x+4)-(2x-3))/(x+4)²= (2x+8-2x+3)/(x+4)²= 11/(x+4)²

f'(-5)= 11/(-5+4)²= 11