resoudre chaque expression (x+1)carré-(x+3)carré =0 (x-7)carré- (2x+5)carré =0

(x+1)²-(x+3)²=0  identité remarquable
(x+1 +x+3) (x+1-x-3) = 0
(2x+4) (-2) = 0
2x+4=0    =>  x=-4/2=-2

(x-7)²-(2x+5)²=0
(x-7+2x+5) (x-7-2x-5)=0
(3x-2) (-x -12) = 0
soit 3x-2=0  => x=2/3
soit -x-12=0 =>  -x=12      => x=-12