Sagot :
E= (8x +5)² - (8x+5)(2x-3)
=64x²+80x+25-(16x²+10x-24x-15)
=48x²+94x+40
E= (8x +5)² - (8x+5)(2x-3)
=(8x+5)(8x+5-2x+3)
=(8x+5)(6x+8)
si x=2/3 alors E=124
E=(8x +5)² - (8x+5)(2x-3)
=(8x+5)(8x+5-2x+3)
=(8x+5)(6x+8)
E= (8x +5)² - (8x+5)(2x-3)
=64x²+80x+25-(16x²+10x-24x-15)
=48x²+94x+40
x=2/3
donc E=124