Sagot :
(a+7)(a+2) = a*a + a*2 + 7*a + 7*2
(a+7)(a+2) = a²+2a+7a+14
(a+7)(a+2) = a² +9a+14
(5+2x)(3x-4) = 15x-20+6x²-8x
(5+2x)(3x-4) = 6x²+7x-20
(a+7)(a+2) = a²+2a+7a+14
(a+7)(a+2) = a² +9a+14
(5+2x)(3x-4) = 15x-20+6x²-8x
(5+2x)(3x-4) = 6x²+7x-20