x^2-15x+90=0

Solution for x^2-15x+90=0 equation:

Simplifying
x2 + -15x + 90 = 0

Reorder the terms:
90 + -15x + x2 = 0

Solving
90 + -15x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '-90' to each side of the equation.
90 + -15x + -90 + x2 = 0 + -90

Reorder the terms:
90 + -90 + -15x + x2 = 0 + -90

Combine like terms: 90 + -90 = 0
0 + -15x + x2 = 0 + -90
-15x + x2 = 0 + -90

Combine like terms: 0 + -90 = -90
-15x + x2 = -90

The x term is -15x.  Take half its coefficient (-7.5).
Square it (56.25) and add it to both sides.

Add '56.25' to each side of the equation.
-15x + 56.25 + x2 = -90 + 56.25

Reorder the terms:
56.25 + -15x + x2 = -90 + 56.25

Combine like terms: -90 + 56.25 = -33.75
56.25 + -15x + x2 = -33.75

Factor a perfect square on the left side:
(x + -7.5)(x + -7.5) = -33.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.