0.33*(21-3a)=6-a

Solution for 0.33*(21-3a)=6-a equation:

Simplifying
0.33(21 + -3a) = 6 + -1a
(21 * 0.33 + -3a * 0.33) = 6 + -1a
(6.93 + -0.99a) = 6 + -1a

Solving
6.93 + -0.99a = 6 + -1a

Solving for variable 'a'.

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

Add 'a' to each side of the equation.
6.93 + -0.99a + a = 6 + -1a + a

Combine like terms: -0.99a + a = 0.01a
6.93 + 0.01a = 6 + -1a + a

Combine like terms: -1a + a = 0
6.93 + 0.01a = 6 + 0
6.93 + 0.01a = 6

Add '-6.93' to each side of the equation.
6.93 + -6.93 + 0.01a = 6 + -6.93

Combine like terms: 6.93 + -6.93 = 0.00
0.00 + 0.01a = 6 + -6.93
0.01a = 6 + -6.93

Combine like terms: 6 + -6.93 = -0.93
0.01a = -0.93

Divide each side by '0.01'.
a = -93

Simplifying
a = -93