bonjour
a (x) = x - 2 x - 3 - 5 x + 1 + 3 x - 2 - x
a(x) = - 4 x - 4
b(x) = x² - 2 x + 3 - 5 x + 5 + 3 x - 2 + x
b(x) = x² - 3 x + 6
c(x) = x ² + 3 x - 2 x - 6 - 5 x + 1 - 3 x² + 2 x
c(x) = - 2 x² - 2 x - 5
d(x) = x - 2 x - 3 + 5 x - 15 x² - 2 + x
d(x) = - 15 x² + 5 x - 5
e(x) = x² - 2 x + 3 - 5 x - ( - 2 - x - 6 x - 3 x²)
e(x) = x² - 2 x + 3 - 5 x + 2 + x + 6 x + 3 x²
e(x) = 4 x² + 5