Answer: - 235
Step-by-step explanation:
f(x) = -3x² + 13x + 3
f(-7) = -3(-7)² + 13(-7) + 3
= -3(49) - 91 + 3
= -147 - 88
= -235
Answer:
x = 5 or x = - [tex]\frac{2}{3}[/tex]
Step-by-step explanation:
given f(x) = - 7, then
- 3x² + 13x + 3 = - 7 ( add 7 to both sides )
- 3x² + 13x + 10 = 0 ← in standard form
Consider the factors of the product of the coefficient of the x² term and the constant term which sum to give the coefficient of the x term
product = - 3 × 10 = - 30 and sum = + 13
The factors are + 15 and - 2
Use these factors to split the middle term
- 3x² + 15x - 2x + 10 = 0 ( factor by grouping the 1/2 and 3/4 terms )
- 3x(x - 5 ) - 2(x - 5 ) = 0 ( factor out (x - 5 ) )
(x - 5)(- 3x - 2) = 0
equate each factor to zero and solve for x
x - 5 = 0 ⇒ x = 5
- 3x - 2 = 0 ⇒ - 3x = 2 ⇒ x = - [tex]\frac{2}{3}[/tex]
