bjr
9b + 6b = 15b
4a - 9a = -5a
x+x+x+x = 4x
4x+x+6x = 11x
2*x*(-4)*y = -8xy
7x * 2x = 14x²
et
A = 8x + 7x² - 3 - 9x² - 2x
= 7x² - 9x² + 8x - 2x - 3
= -2x² + 6x - 3
