Answer:
-y(y + 7) = 0
_________
y = 0
y = -7
Step-by-step explanation:
-7y – y^2=0
y(-7-y) = 0
[y can be factored out because -7y and y² are both multiplied by y, -7y and -y² = -7(y) and -y(y). They have a common variable factor of y]
-y(7 + y) = 0
[-1 can also be factored out because -7 and -y both have a negative]
-y(7 + y) = 0 → -y = 0 and (7 + y) = 0.
-y = 0 → -y÷-1 = 0÷-1 → y = 0
(7 + y) = 0 → 7 + y – 7 = 0 – 7 → y = -7
