(7x^2-x+4)+(-2x^2+5x+3)=

Solution for (7x^2-x+4)+(-2x^2+5x+3)= equation:

Simplifying
(7x2 + -1x + 4) + (-2x2 + 5x + 3) = 0

Reorder the terms:
(4 + -1x + 7x2) + (-2x2 + 5x + 3) = 0

Remove parenthesis around (4 + -1x + 7x2)
4 + -1x + 7x2 + (-2x2 + 5x + 3) = 0

Reorder the terms:
4 + -1x + 7x2 + (3 + 5x + -2x2) = 0

Remove parenthesis around (3 + 5x + -2x2)
4 + -1x + 7x2 + 3 + 5x + -2x2 = 0

Reorder the terms:
4 + 3 + -1x + 5x + 7x2 + -2x2 = 0

Combine like terms: 4 + 3 = 7
7 + -1x + 5x + 7x2 + -2x2 = 0

Combine like terms: -1x + 5x = 4x
7 + 4x + 7x2 + -2x2 = 0

Combine like terms: 7x2 + -2x2 = 5x2
7 + 4x + 5x2 = 0

Solving
7 + 4x + 5x2 = 0

Solving for variable 'x'.

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

Divide each side by '5'.
1.4 + 0.8x + x2 = 0

Move the constant term to the right:

Add '-1.4' to each side of the equation.
1.4 + 0.8x + -1.4 + x2 = 0 + -1.4

Reorder the terms:
1.4 + -1.4 + 0.8x + x2 = 0 + -1.4

Combine like terms: 1.4 + -1.4 = 0.0
0.0 + 0.8x + x2 = 0 + -1.4
0.8x + x2 = 0 + -1.4

Combine like terms: 0 + -1.4 = -1.4
0.8x + x2 = -1.4

The x term is 0.8x.  Take half its coefficient (0.4).
Square it (0.16) and add it to both sides.

Add '0.16' to each side of the equation.
0.8x + 0.16 + x2 = -1.4 + 0.16

Reorder the terms:
0.16 + 0.8x + x2 = -1.4 + 0.16

Combine like terms: -1.4 + 0.16 = -1.24
0.16 + 0.8x + x2 = -1.24

Factor a perfect square on the left side:
(x + 0.4)(x + 0.4) = -1.24

Can't calculate square root of the right side.

The solution to this equation could not be determined.