0.4y^2-1.2y^2+6.6-1.8=

Solution for 0.4y^2-1.2y^2+6.6-1.8= equation:

Simplifying
0.4y2 + -1.2y2 + 6.6 + -1.8 = 0

Reorder the terms:
6.6 + -1.8 + 0.4y2 + -1.2y2 = 0

Combine like terms: 6.6 + -1.8 = 4.8
4.8 + 0.4y2 + -1.2y2 = 0

Combine like terms: 0.4y2 + -1.2y2 = -0.8y2
4.8 + -0.8y2 = 0

Solving
4.8 + -0.8y2 = 0

Solving for variable 'y'.

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

Add '-4.8' to each side of the equation.
4.8 + -4.8 + -0.8y2 = 0 + -4.8

Combine like terms: 4.8 + -4.8 = 0.0
0.0 + -0.8y2 = 0 + -4.8
-0.8y2 = 0 + -4.8

Combine like terms: 0 + -4.8 = -4.8
-0.8y2 = -4.8

Divide each side by '-0.8'.
y2 = 6

Simplifying
y2 = 6

Take the square root of each side:
y = {-2.449489743, 2.449489743}