4(y+-9)=2(y+21)

Solution for 4(y+-9)=2(y+21) equation:

Simplifying
4(y + -9) = 2(y + 21)

Reorder the terms:
4(-9 + y) = 2(y + 21)
(-9 * 4 + y * 4) = 2(y + 21)
(-36 + 4y) = 2(y + 21)

Reorder the terms:
-36 + 4y = 2(21 + y)
-36 + 4y = (21 * 2 + y * 2)
-36 + 4y = (42 + 2y)

Solving
-36 + 4y = 42 + 2y

Solving for variable 'y'.

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

Add '-2y' to each side of the equation.
-36 + 4y + -2y = 42 + 2y + -2y

Combine like terms: 4y + -2y = 2y
-36 + 2y = 42 + 2y + -2y

Combine like terms: 2y + -2y = 0
-36 + 2y = 42 + 0
-36 + 2y = 42

Add '36' to each side of the equation.
-36 + 36 + 2y = 42 + 36

Combine like terms: -36 + 36 = 0
0 + 2y = 42 + 36
2y = 42 + 36

Combine like terms: 42 + 36 = 78
2y = 78

Divide each side by '2'.
y = 39

Simplifying
y = 39