Bonsoir!
f(x) = (6 - x)(x - 1) + 18 - 3x
1) f(x) = (6 - x)(x - 1) + 18 - 3x
f(x) = 6x - 6 - x² + 1x + 18 - 3x
f(x) = - x² + 4x - 12
2) f(x) = (6 - x)(x - 1) + 18 - 3x
f(x) = (6 - x)(x - 1) + 3(6 - x) ← a * b + c * a = a (b + c)
f(x) = (6 - x)(x - 1 + 3)
f(x) = (6 - x)(x + 2)
3) f(x) = 16 - (x - 2)²
f(x) = 4² - (x - 2)² ← a² - b² = (a - b)(a + b)
f(x) = (4 - x + 2)(4 + x - 2)
f(x) = (6 - x)(x + 2)
En espérant t'avoir aidé!
