Dévelopé et réduire les expressions: a) (5x-7)^+(9x-4)^ b) (5x-7)^-(9x-4)^ ^= au carrée merci ;)

Développer et Réduire :
a) (5x-7)²+(9x-4)²
 = (25x² - 70x +49 ) +(81x² - 72x +16)
= 25x² +81x² -70x -72x +49 +46
= 106x² -142x +65
b) (5x-7)²-(9x-4)²
= (25x² - 70x +49 ) - (81x² - 72x +16)
= 25x² -81x² -70x +72x +49 -16
= -56x² + 2x +33

a.
(5x-7)^+(9x-4)^
=25x^-2*5x*7+49+81x^-2*9x*4+16
=25x^-70x+49+81x^-72x+16
=106x^-142x+65

b.
(5x-7)^-(9x-4)^
=(5x-7+9x-4)(5x-7-9x+4)
=(14x-11)(-4x-3)
=-56x-42x+44x+33
=-.98x+44 X+33
=.&