5-2[p-(3+2p)]=21

Solution for 5-2[p-(3+2p)]=21 equation:

Simplifying
5 + -2[p + -1(3 + 2p)] = 21
5 + -2[p + (3 * -1 + 2p * -1)] = 21
5 + -2[p + (-3 + -2p)] = 21

Reorder the terms:
5 + -2[-3 + p + -2p] = 21

Combine like terms: p + -2p = -1p
5 + -2[-3 + -1p] = 21
5 + [-3 * -2 + -1p * -2] = 21
5 + [6 + 2p] = 21

Combine like terms: 5 + 6 = 11
11 + 2p = 21

Solving
11 + 2p = 21

Solving for variable 'p'.

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

Add '-11' to each side of the equation.
11 + -11 + 2p = 21 + -11

Combine like terms: 11 + -11 = 0
0 + 2p = 21 + -11
2p = 21 + -11

Combine like terms: 21 + -11 = 10
2p = 10

Divide each side by '2'.
p = 5

Simplifying
p = 5