Answer:
a = −1 or a = 7
Explanation:
Let's solve your equation step-by-step.
( a − 7 ) ( a + 1 ) = 0
Step 1: Simplify both sides of the equation.
a^2 − 6a − 7 = 0
Step 2: Factor left side of equation.
( a + 1 ) ( a − 7 ) = 0
Step 3: Set factors equal to 0.
a + 1 = 0 or a − 7 = 0
a = −1 or a = 7