Aidez moi s'il vous plait exercice 5!!!!

f(x)=3*(2x-1)-4(5-8x)
f(x)=6x-3-20+32x
f(x)=38x-23

g(x)=(x+3)/4+(2x-1)/5
g(x)=(5(x+3)+4(2x-1))/20
g(x)=(5x+15+8x-4)/20
g(x)=(13x+11)/20

h(x)=(9+4x)²-(2-x)²
h(x)=81+36x+36x+16x²-(4-4x+x²)
h(x)=81+72x+16x²-4+4x-x²
h(x)=15x²+76x+77

k(x)=-(7x²)-(-7x)²+(2-x)(2+x)
k(x)=-7x²-49x²+4+2x-2x-x²
k(x)=-57x²+4