Bonjour je n'arrive pas cet exercice​

Bonjour
a) Df = ]-infini;+infini[
b) f(2) = (2x2-1)/(2+2)
f(2)= 3/4
c) 4= (2x-1)/(x+2)
4 x (x+2) = (2x-1)/(x+2) x (x+2)
4x +8 -2x -8 = 2x-1 -2x -8
2x = -9
2x/2 = -9/2
x= -4,5