Sagot :
B = 3 × x + 3 × 5 - x × x - x × 5
= 3x + 15 - x^2 - 5x
= - x^2 - 2x + 15
D = x × 3x + x × 4 - 1 × 3x - 1 × 4
= 3x^2 + 4x - 3x - 4
= 3x^2 + x - 4
Bonjour,
B=(3-x)(x+5)
B=3*x+3*5-x*x-x*5
B=3x+15-x²-5x
B=-x²-2x+15
D=(x-1)(3x+4)
D=x*3x+x*4-1*3x-1*4
D=3x²+4x-3x-4
D=3x²+x-4