3*21=x

Solution for 3*21=x equation:

Simplifying
3 * 21 = x

Multiply 3 * 21
63 = x

Solving
63 = x

Solving for variable 'x'.

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

Add '-1x' to each side of the equation.
63 + -1x = x + -1x

Combine like terms: x + -1x = 0
63 + -1x = 0

Add '-63' to each side of the equation.
63 + -63 + -1x = 0 + -63

Combine like terms: 63 + -63 = 0
0 + -1x = 0 + -63
-1x = 0 + -63

Combine like terms: 0 + -63 = -63
-1x = -63

Divide each side by '-1'.
x = 63

Simplifying
x = 63