Answer:
y = - x² - 4x - 9
Step-by-step explanation:
Given
y = - (x + 2)² - 5 ← expand (x + 2)² using FOIL
= - (x² + 4x + 4) - 5 ← distribute parenthesis by - 1
= - x² - 4x - 4 - 5 ← collect like terms
= - x² - 4x - 9 ← in standard form
Your formula for this is

and

. Get everything on one side of the equals sign, set it equal to 0 and factor. When you do this you get (x-3)(x+27). The Zero Product Property rule tells us that either x-3 = 0 or x+27 = 0 and that x = 3 and -27. The only thing in math that will NEVER be negative besides time is distance/length, therefore, x cannot be 27 and has to be 3.
Step-by-step explanation:
(2x³y^-4)^-2 = 1/(4x⁶y^‐8) = y⁸/(4x⁶)
1/(8x⁵y^-7) = y⁷/(8x⁵)
4x^-9y⁴ = 4y⁴/x⁹
so, the whole expression is then
y⁸/(4x⁶) × y⁷/(8x⁵) × 4y⁴/x⁹
4y¹⁹/(32x²⁰) = y¹⁹/(8x²⁰)
so, D is the correct answer.