(a+7)(a-1)=

Solution for (a+7)(a-1)= equation:

Simplifying
(a + 7)(a + -1) = 0

Reorder the terms:
(7 + a)(a + -1) = 0

Reorder the terms:
(7 + a)(-1 + a) = 0

Multiply (7 + a) * (-1 + a)
(7(-1 + a) + a(-1 + a)) = 0
((-1 * 7 + a * 7) + a(-1 + a)) = 0
((-7 + 7a) + a(-1 + a)) = 0
(-7 + 7a + (-1 * a + a * a)) = 0
(-7 + 7a + (-1a + a2)) = 0

Combine like terms: 7a + -1a = 6a
(-7 + 6a + a2) = 0

Solving
-7 + 6a + a2 = 0

Solving for variable 'a'.

Factor a trinomial.
(-7 + -1a)(1 + -1a) = 0

Subproblem 1
Set the factor '(-7 + -1a)' equal to zero and attempt to solve:

Simplifying
-7 + -1a = 0

Solving
-7 + -1a = 0

Move all terms containing a to the left, all other terms to the right.

Add '7' to each side of the equation.
-7 + 7 + -1a = 0 + 7

Combine like terms: -7 + 7 = 0
0 + -1a = 0 + 7
-1a = 0 + 7

Combine like terms: 0 + 7 = 7
-1a = 7

Divide each side by '-1'.
a = -7

Simplifying
a = -7
Subproblem 2
Set the factor '(1 + -1a)' equal to zero and attempt to solve:

Simplifying
1 + -1a = 0

Solving
1 + -1a = 0

Move all terms containing a to the left, all other terms to the right.

Add '-1' to each side of the equation.
1 + -1 + -1a = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -1a = 0 + -1
-1a = 0 + -1

Combine like terms: 0 + -1 = -1
-1a = -1

Divide each side by '-1'.
a = 1

Simplifying
a = 1
Solution
a = {-7, 1}