400y^2-9=

Solution for 400y^2-9= equation:

Simplifying
400y2 + -9 = 0

Reorder the terms:
-9 + 400y2 = 0

Solving
-9 + 400y2 = 0

Solving for variable 'y'.

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

Add '9' to each side of the equation.
-9 + 9 + 400y2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + 400y2 = 0 + 9
400y2 = 0 + 9

Combine like terms: 0 + 9 = 9
400y2 = 9

Divide each side by '400'.
y2 = 0.0225

Simplifying
y2 = 0.0225

Take the square root of each side:
y = {-0.15, 0.15}