400-300=y

Solution for 400-300=y equation:

Simplifying
400 + -300 = y

Combine like terms: 400 + -300 = 100
100 = y

Solving
100 = 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.
100 + -1y = y + -1y

Combine like terms: y + -1y = 0
100 + -1y = 0

Add '-100' to each side of the equation.
100 + -100 + -1y = 0 + -100

Combine like terms: 100 + -100 = 0
0 + -1y = 0 + -100
-1y = 0 + -100

Combine like terms: 0 + -100 = -100
-1y = -100

Divide each side by '-1'.
y = 100

Simplifying
y = 100