0.8x(4x-3)+0.3(7-10x)=-0.2

Solution for 0.8x(4x-3)+0.3(7-10x)=-0.2 equation:

Simplifying
0.8x(4x + -3) + 0.3(7 + -10x) = -0.2

Reorder the terms:
0.8x(-3 + 4x) + 0.3(7 + -10x) = -0.2
(-3 * 0.8x + 4x * 0.8x) + 0.3(7 + -10x) = -0.2
(-2.4x + 3.2x2) + 0.3(7 + -10x) = -0.2
-2.4x + 3.2x2 + (7 * 0.3 + -10x * 0.3) = -0.2
-2.4x + 3.2x2 + (2.1 + -3x) = -0.2

Reorder the terms:
2.1 + -2.4x + -3x + 3.2x2 = -0.2

Combine like terms: -2.4x + -3x = -5.4x
2.1 + -5.4x + 3.2x2 = -0.2

Solving
2.1 + -5.4x + 3.2x2 = -0.2

Solving for variable 'x'.

Reorder the terms:
2.1 + 0.2 + -5.4x + 3.2x2 = -0.2 + 0.2

Combine like terms: 2.1 + 0.2 = 2.3
2.3 + -5.4x + 3.2x2 = -0.2 + 0.2

Combine like terms: -0.2 + 0.2 = 0.0
2.3 + -5.4x + 3.2x2 = 0.0

Begin completing the square.  Divide all terms by
3.2 the coefficient of the squared term: 

Divide each side by '3.2'.
0.71875 + -1.6875x + x2 = 0

Move the constant term to the right:

Add '-0.71875' to each side of the equation.
0.71875 + -1.6875x + -0.71875 + x2 = 0 + -0.71875

Reorder the terms:
0.71875 + -0.71875 + -1.6875x + x2 = 0 + -0.71875

Combine like terms: 0.71875 + -0.71875 = 0.00000
0.00000 + -1.6875x + x2 = 0 + -0.71875
-1.6875x + x2 = 0 + -0.71875

Combine like terms: 0 + -0.71875 = -0.71875
-1.6875x + x2 = -0.71875

The x term is -1.6875x.  Take half its coefficient (-0.84375).
Square it (0.7119140625) and add it to both sides.

Add '0.7119140625' to each side of the equation.
-1.6875x + 0.7119140625 + x2 = -0.71875 + 0.7119140625

Reorder the terms:
0.7119140625 + -1.6875x + x2 = -0.71875 + 0.7119140625

Combine like terms: -0.71875 + 0.7119140625 = -0.0068359375
0.7119140625 + -1.6875x + x2 = -0.0068359375

Factor a perfect square on the left side:
(x + -0.84375)(x + -0.84375) = -0.0068359375

Can't calculate square root of the right side.

The solution to this equation could not be determined.