(21-2p)-(15+6p)=0

Solution for (21-2p)-(15+6p)=0 equation:

Simplifying
(21 + -2p) + -1(15 + 6p) = 0

Remove parenthesis around (21 + -2p)
21 + -2p + -1(15 + 6p) = 0
21 + -2p + (15 * -1 + 6p * -1) = 0
21 + -2p + (-15 + -6p) = 0

Reorder the terms:
21 + -15 + -2p + -6p = 0

Combine like terms: 21 + -15 = 6
6 + -2p + -6p = 0

Combine like terms: -2p + -6p = -8p
6 + -8p = 0

Solving
6 + -8p = 0

Solving for variable 'p'.

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

Add '-6' to each side of the equation.
6 + -6 + -8p = 0 + -6

Combine like terms: 6 + -6 = 0
0 + -8p = 0 + -6
-8p = 0 + -6

Combine like terms: 0 + -6 = -6
-8p = -6

Divide each side by '-8'.
p = 0.75

Simplifying
p = 0.75