Move to the left side of the equation by subtracting it from both sides.

Subtract from .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Factor out of .

Divide each term in by .

Cancel the common factor of .

Divide by .

Use the quadratic formula to find the solutions.

Substitute the values , , and into the quadratic formula and solve for .

Simplify the numerator.

Raise to the power of .

Multiply by .

Multiply by .

Subtract from .

Rewrite as .

Rewrite as .

Rewrite as .

Rewrite as .

Factor out of .

Rewrite as .

Pull terms out from under the radical.

Move to the left of .

Multiply by .

Simplify .

The final answer is the combination of both solutions.

Solve for x 0.75x^2-x+400=8.75