2(5a+1)+2(a+1)=90

Solution for 2(5a+1)+2(a+1)=90 equation:

Simplifying
2(5a + 1) + 2(a + 1) = 90

Reorder the terms:
2(1 + 5a) + 2(a + 1) = 90
(1 * 2 + 5a * 2) + 2(a + 1) = 90
(2 + 10a) + 2(a + 1) = 90

Reorder the terms:
2 + 10a + 2(1 + a) = 90
2 + 10a + (1 * 2 + a * 2) = 90
2 + 10a + (2 + 2a) = 90

Reorder the terms:
2 + 2 + 10a + 2a = 90

Combine like terms: 2 + 2 = 4
4 + 10a + 2a = 90

Combine like terms: 10a + 2a = 12a
4 + 12a = 90

Solving
4 + 12a = 90

Solving for variable 'a'.

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

Add '-4' to each side of the equation.
4 + -4 + 12a = 90 + -4

Combine like terms: 4 + -4 = 0
0 + 12a = 90 + -4
12a = 90 + -4

Combine like terms: 90 + -4 = 86
12a = 86

Divide each side by '12'.
a = 7.166666667

Simplifying
a = 7.166666667