(0.7x^2+0.3x-0.9)-(0.9x^2+1.4)=

Solution for (0.7x^2+0.3x-0.9)-(0.9x^2+1.4)= equation:

Simplifying
(0.7x2 + 0.3x + -0.9) + -1(0.9x2 + 1.4) = 0

Reorder the terms:
(-0.9 + 0.3x + 0.7x2) + -1(0.9x2 + 1.4) = 0

Remove parenthesis around (-0.9 + 0.3x + 0.7x2)
-0.9 + 0.3x + 0.7x2 + -1(0.9x2 + 1.4) = 0

Reorder the terms:
-0.9 + 0.3x + 0.7x2 + -1(1.4 + 0.9x2) = 0
-0.9 + 0.3x + 0.7x2 + (1.4 * -1 + 0.9x2 * -1) = 0
-0.9 + 0.3x + 0.7x2 + (-1.4 + -0.9x2) = 0

Reorder the terms:
-0.9 + -1.4 + 0.3x + 0.7x2 + -0.9x2 = 0

Combine like terms: -0.9 + -1.4 = -2.3
-2.3 + 0.3x + 0.7x2 + -0.9x2 = 0

Combine like terms: 0.7x2 + -0.9x2 = -0.2x2
-2.3 + 0.3x + -0.2x2 = 0

Solving
-2.3 + 0.3x + -0.2x2 = 0

Solving for variable 'x'.

Begin completing the square.  Divide all terms by
-0.2 the coefficient of the squared term: 

Divide each side by '-0.2'.
11.5 + -1.5x + x2 = 0

Move the constant term to the right:

Add '-11.5' to each side of the equation.
11.5 + -1.5x + -11.5 + x2 = 0 + -11.5

Reorder the terms:
11.5 + -11.5 + -1.5x + x2 = 0 + -11.5

Combine like terms: 11.5 + -11.5 = 0.0
0.0 + -1.5x + x2 = 0 + -11.5
-1.5x + x2 = 0 + -11.5

Combine like terms: 0 + -11.5 = -11.5
-1.5x + x2 = -11.5

The x term is -1.5x.  Take half its coefficient (-0.75).
Square it (0.5625) and add it to both sides.

Add '0.5625' to each side of the equation.
-1.5x + 0.5625 + x2 = -11.5 + 0.5625

Reorder the terms:
0.5625 + -1.5x + x2 = -11.5 + 0.5625

Combine like terms: -11.5 + 0.5625 = -10.9375
0.5625 + -1.5x + x2 = -10.9375

Factor a perfect square on the left side:
(x + -0.75)(x + -0.75) = -10.9375

Can't calculate square root of the right side.

The solution to this equation could not be determined.