A^2-36=5a

A. {4,-9}
B. {5+√61/2, 5-√61/2}
C. No solution
D. {9,-4}

The answer is D. ( 9, -4)

because we are solving for a

Step-by-step explanation:

Move all terms to the left side and set equal to zero. Then set each factor equal to zero.

D

Step-by-step explanation:

Given

a² - 36 = 5a ( subtract 5a from both sides )

a² - 5a - 36 = 0

Consider the factors of the constant term (- 36) which sum to give the coefficient of the a- term (- 5)

The factors are - 9 and + 4 , since

- 9 × + 4 = - 36 and - 9 + 4 = - 5 , then

(a - 9)(a + 4) = 0 ← in factored form

Equate each factor to zero and solve for a

a - 9 = 0 ⇒ a = 9

a + 4 = 0 ⇒ a = - 4

solution is { - 9, 4 } → D

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.