3+-1y-5y=7(3+-1y)+2y-21

Solution for 3+-1y-5y=7(3+-1y)+2y-21 equation:

Simplifying
3 + -1y + -5y = 7(3 + -1y) + 2y + -21

Combine like terms: -1y + -5y = -6y
3 + -6y = 7(3 + -1y) + 2y + -21
3 + -6y = (3 * 7 + -1y * 7) + 2y + -21
3 + -6y = (21 + -7y) + 2y + -21

Reorder the terms:
3 + -6y = 21 + -21 + -7y + 2y

Combine like terms: 21 + -21 = 0
3 + -6y = 0 + -7y + 2y
3 + -6y = -7y + 2y

Combine like terms: -7y + 2y = -5y
3 + -6y = -5y

Solving
3 + -6y = -5y

Solving for variable 'y'.

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

Add '5y' to each side of the equation.
3 + -6y + 5y = -5y + 5y

Combine like terms: -6y + 5y = -1y
3 + -1y = -5y + 5y

Combine like terms: -5y + 5y = 0
3 + -1y = 0

Add '-3' to each side of the equation.
3 + -3 + -1y = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1y = 0 + -3
-1y = 0 + -3

Combine like terms: 0 + -3 = -3
-1y = -3

Divide each side by '-1'.
y = 3

Simplifying
y = 3