(u-7)(u+1)=

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

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

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

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

Multiply (-7 + u) * (1 + u)
(-7(1 + u) + u(1 + u)) = 0
((1 * -7 + u * -7) + u(1 + u)) = 0
((-7 + -7u) + u(1 + u)) = 0
(-7 + -7u + (1 * u + u * u)) = 0
(-7 + -7u + (1u + u2)) = 0

Combine like terms: -7u + 1u = -6u
(-7 + -6u + u2) = 0

Solving
-7 + -6u + u2 = 0

Solving for variable 'u'.

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

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

Simplifying
-1 + -1u = 0

Solving
-1 + -1u = 0

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

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

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

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

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

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

Simplifying
7 + -1u = 0

Solving
7 + -1u = 0

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

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

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

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

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

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