merci de m aidez c trip dure

Aire : (9x-4)^2=(9x-4)(9x-4)
=81x^2-36x-36x+16
=81x^2-72x+16
Lorsque x=2/3 : 81*(2/3)^2-72*2/3+16
=81*(4/9)-48+16
=36-48+16=4

bonjour,

A carré = (9x-4)²
81x²-72x+16

pour x = 2/3
81(2/3)² -72*2/3 +16 =
81*4/9 - 144/3 +16 =
36-48+16 = 4