21+4a-(a-1)=a

Solution for 21+4a-(a-1)=a equation:

Simplifying
21 + 4a + -1(a + -1) = a

Reorder the terms:
21 + 4a + -1(-1 + a) = a
21 + 4a + (-1 * -1 + a * -1) = a
21 + 4a + (1 + -1a) = a

Reorder the terms:
21 + 1 + 4a + -1a = a

Combine like terms: 21 + 1 = 22
22 + 4a + -1a = a

Combine like terms: 4a + -1a = 3a
22 + 3a = a

Solving
22 + 3a = a

Solving for variable 'a'.

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

Add '-1a' to each side of the equation.
22 + 3a + -1a = a + -1a

Combine like terms: 3a + -1a = 2a
22 + 2a = a + -1a

Combine like terms: a + -1a = 0
22 + 2a = 0

Add '-22' to each side of the equation.
22 + -22 + 2a = 0 + -22

Combine like terms: 22 + -22 = 0
0 + 2a = 0 + -22
2a = 0 + -22

Combine like terms: 0 + -22 = -22
2a = -22

Divide each side by '2'.
a = -11

Simplifying
a = -11