Bonsoir,
1. f(2) = -4 * 2 + 5
= -8 + 5
= -3.
2. On résout f(x) = -7
<=> -4x + 5 = -7
<=> -4x = -12
<=> x = 12/4 = 3.
3. g(-1) = (-1)² - 6 * (-1) + 6
= 1 + 6 + 6
= 13.
4. On résout g(x) = -3
<=< x² -6x + 6 = -3
<=< x² - 6x + 9 = 0
<=> (x - 3)² = 0
<=> √(x-3)² = √0
<=> x - 3 = 0
<=> x = 3.
