Answer:
q = 15
Step-by-step explanation:
Given
f(x) = x² + px + q , then
f(3) = 3² + 3p + q = 6 , that is
9 + 3p + q = 6 ( subtract 9 from both sides )
3p + q = - 3 → (1)
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f'(x) = 2x + p , then
f'(3) = 2(3) + p = 0, that is
6 + p = 0 ( subtract 6 from both sides )
p = - 6
Substitute p = - 6 into (1)
3(- 6) + q = - 3
- 18 + q = - 3 ( add 18 to both sides )
q = 15
