(x+1)(x-2)=4

Solution for (x+1)(x-2)=4 equation:

Simplifying
(x + 1)(x + -2) = 4

Reorder the terms:
(1 + x)(x + -2) = 4

Reorder the terms:
(1 + x)(-2 + x) = 4

Multiply (1 + x) * (-2 + x)
(1(-2 + x) + x(-2 + x)) = 4
((-2 * 1 + x * 1) + x(-2 + x)) = 4
((-2 + 1x) + x(-2 + x)) = 4
(-2 + 1x + (-2 * x + x * x)) = 4
(-2 + 1x + (-2x + x2)) = 4

Combine like terms: 1x + -2x = -1x
(-2 + -1x + x2) = 4

Solving
-2 + -1x + x2 = 4

Solving for variable 'x'.

Reorder the terms:
-2 + -4 + -1x + x2 = 4 + -4

Combine like terms: -2 + -4 = -6
-6 + -1x + x2 = 4 + -4

Combine like terms: 4 + -4 = 0
-6 + -1x + x2 = 0

Factor a trinomial.
(-2 + -1x)(3 + -1x) = 0

Subproblem 1
Set the factor '(-2 + -1x)' equal to zero and attempt to solve:

Simplifying
-2 + -1x = 0

Solving
-2 + -1x = 0

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

Add '2' to each side of the equation.
-2 + 2 + -1x = 0 + 2

Combine like terms: -2 + 2 = 0
0 + -1x = 0 + 2
-1x = 0 + 2

Combine like terms: 0 + 2 = 2
-1x = 2

Divide each side by '-1'.
x = -2

Simplifying
x = -2
Subproblem 2
Set the factor '(3 + -1x)' equal to zero and attempt to solve:

Simplifying
3 + -1x = 0

Solving
3 + -1x = 0

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

Add '-3' to each side of the equation.
3 + -3 + -1x = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1x = 0 + -3
-1x = 0 + -3

Combine like terms: 0 + -3 = -3
-1x = -3

Divide each side by '-1'.
x = 3

Simplifying
x = 3
Solution
x = {-2, 3}