Exercice 132 aider moi c'est urgent svp

1/
h =(x-4)² -x(x-10)
= x²-8x+16 -x²+10x
=2x+16

2/
2x+16 =16
2x =16-16
2x =0
x =0/2
x =0

3/
i= (7x-3)²-5²
(7x-3-5)(7x-3+5)
(7x-8)(7x+2)

4/
(7x-8)(7x+2) =0

7x-8 =0                     7x+2 =0
7x =8                           7x = -2
x = 8/7                           x = -2/7