b)
A= 7*9+7*(-3)+x*9x+x*(-3)
= 63x - 21 + 9x² - 3x
= 9x² + 63x - 3x -21
= 9x² + 60x - 21
C= 2x*5x+2x*3+4*5x+4*3
= 10x² + 6x + 20x + 12
= 10x² + 26x + 12
B= -6*3x-6*(-1)+2x*3x+2x(-1)
= -18x + 6 + 6x²-2x
= 6x² - 18x - 2x + 6
= 6x² - 20x - 6
D= x*8+x*(-5x)-4*8-4*(-5x)
= 8x - 5x² - 32 + 20x
= -5x² + 8x + 20x -32
= -5x² + 28x - 32
a)
1er tableau
7 * 9x = 63x
7 * (-3) = -21
x * 9x = 9x²
x * (-3) = -3X
2eme tableau
-6 * 3x = -18x
-6 * (-1) = 6
2x * 3x =6x²
2x * (-1) = -2x
