Sagot :
B= 9x(x-9) - (7x+2)²
B= 9x* x- 9x* 9- 7x²+2*7x*2+2², B=9x²-81x-7x²+28x+4,B= 2x²-53x+4
A=(7x+4)²+(9x-3)²
A= (7x²+2*7x*4+4²)- (9x²-2*9x*3+3²), A= 7x²+42x+16+9x²-54x+9, A= 16x²-12x+25
B= 9x* x- 9x* 9- 7x²+2*7x*2+2², B=9x²-81x-7x²+28x+4,B= 2x²-53x+4
A=(7x+4)²+(9x-3)²
A= (7x²+2*7x*4+4²)- (9x²-2*9x*3+3²), A= 7x²+42x+16+9x²-54x+9, A= 16x²-12x+25