2x+3(2x-1)=21

Solution for 2x+3(2x-1)=21 equation:

Simplifying
2x + 3(2x + -1) = 21

Reorder the terms:
2x + 3(-1 + 2x) = 21
2x + (-1 * 3 + 2x * 3) = 21
2x + (-3 + 6x) = 21

Reorder the terms:
-3 + 2x + 6x = 21

Combine like terms: 2x + 6x = 8x
-3 + 8x = 21

Solving
-3 + 8x = 21

Solving for variable 'x'.

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

Add '3' to each side of the equation.
-3 + 3 + 8x = 21 + 3

Combine like terms: -3 + 3 = 0
0 + 8x = 21 + 3
8x = 21 + 3

Combine like terms: 21 + 3 = 24
8x = 24

Divide each side by '8'.
x = 3

Simplifying
x = 3