(3+x)(6+x)=70

Solution for (3+x)(6+x)=70 equation:

Simplifying
(3 + x)(6 + x) = 70

Multiply (3 + x) * (6 + x)
(3(6 + x) + x(6 + x)) = 70
((6 * 3 + x * 3) + x(6 + x)) = 70
((18 + 3x) + x(6 + x)) = 70
(18 + 3x + (6 * x + x * x)) = 70
(18 + 3x + (6x + x2)) = 70

Combine like terms: 3x + 6x = 9x
(18 + 9x + x2) = 70

Solving
18 + 9x + x2 = 70

Solving for variable 'x'.

Reorder the terms:
18 + -70 + 9x + x2 = 70 + -70

Combine like terms: 18 + -70 = -52
-52 + 9x + x2 = 70 + -70

Combine like terms: 70 + -70 = 0
-52 + 9x + x2 = 0

Factor a trinomial.
(-13 + -1x)(4 + -1x) = 0

Subproblem 1
Set the factor '(-13 + -1x)' equal to zero and attempt to solve:

Simplifying
-13 + -1x = 0

Solving
-13 + -1x = 0

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

Add '13' to each side of the equation.
-13 + 13 + -1x = 0 + 13

Combine like terms: -13 + 13 = 0
0 + -1x = 0 + 13
-1x = 0 + 13

Combine like terms: 0 + 13 = 13
-1x = 13

Divide each side by '-1'.
x = -13

Simplifying
x = -13
Subproblem 2
Set the factor '(4 + -1x)' equal to zero and attempt to solve:

Simplifying
4 + -1x = 0

Solving
4 + -1x = 0

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

Add '-4' to each side of the equation.
4 + -4 + -1x = 0 + -4

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

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

Divide each side by '-1'.
x = 4

Simplifying
x = 4
Solution
x = {-13, 4}