42=15Y-8Y

Solution for 42=15Y-8Y equation:

Simplifying
42 = 15Y + -8Y

Combine like terms: 15Y + -8Y = 7Y
42 = 7Y

Solving
42 = 7Y

Solving for variable 'Y'.

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

Add '-7Y' to each side of the equation.
42 + -7Y = 7Y + -7Y

Combine like terms: 7Y + -7Y = 0
42 + -7Y = 0

Add '-42' to each side of the equation.
42 + -42 + -7Y = 0 + -42

Combine like terms: 42 + -42 = 0
0 + -7Y = 0 + -42
-7Y = 0 + -42

Combine like terms: 0 + -42 = -42
-7Y = -42

Divide each side by '-7'.
Y = 6

Simplifying
Y = 6