-4+2(1+5a)=20

Solution for -4+2(1+5a)=20 equation:

Simplifying
-4 + 2(1 + 5a) = 20
-4 + (1 * 2 + 5a * 2) = 20
-4 + (2 + 10a) = 20

Combine like terms: -4 + 2 = -2
-2 + 10a = 20

Solving
-2 + 10a = 20

Solving for variable 'a'.

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

Add '2' to each side of the equation.
-2 + 2 + 10a = 20 + 2

Combine like terms: -2 + 2 = 0
0 + 10a = 20 + 2
10a = 20 + 2

Combine like terms: 20 + 2 = 22
10a = 22

Divide each side by '10'.
a = 2.2

Simplifying
a = 2.2