Answer:
f(x) = (x + 5)² - 21.5
Step-by-step explanation:
Step 1: Subtract both sides by 7
2x² + 20x = -7
Step: GCF and divide
2(x² + 10x) = -7
x² + 10x = -7/2
Step 3: Complete the Square
x² + 10x + 25 = -7/2 + 25
(x +5)² = 43/2
Step 4: Subtract 43/2 to both sides
(x + 5)² - 43/2
And we have our equation!