3+9=y+4-10

Solution for 3+9=y+4-10 equation:

Simplifying
3 + 9 = y + 4 + -10

Combine like terms: 3 + 9 = 12
12 = y + 4 + -10

Reorder the terms:
12 = 4 + -10 + y

Combine like terms: 4 + -10 = -6
12 = -6 + y

Solving
12 = -6 + y

Solving for variable 'y'.

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

Add '-1y' to each side of the equation.
12 + -1y = -6 + y + -1y

Combine like terms: y + -1y = 0
12 + -1y = -6 + 0
12 + -1y = -6

Add '-12' to each side of the equation.
12 + -12 + -1y = -6 + -12

Combine like terms: 12 + -12 = 0
0 + -1y = -6 + -12
-1y = -6 + -12

Combine like terms: -6 + -12 = -18
-1y = -18

Divide each side by '-1'.
y = 18

Simplifying
y = 18