21=13(x*2)

Solution for 21=13(x*2) equation:

Simplifying
21 = 13(x * 2)

Reorder the terms for easier multiplication:
21 = 13(2x)

Remove parenthesis around (2x)
21 = 13 * 2x

Multiply 13 * 2
21 = 26x

Solving
21 = 26x

Solving for variable 'x'.

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

Add '-26x' to each side of the equation.
21 + -26x = 26x + -26x

Combine like terms: 26x + -26x = 0
21 + -26x = 0

Add '-21' to each side of the equation.
21 + -21 + -26x = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -26x = 0 + -21
-26x = 0 + -21

Combine like terms: 0 + -21 = -21
-26x = -21

Divide each side by '-26'.
x = 0.8076923077

Simplifying
x = 0.8076923077