(x-10)(x-9)=-78

Solution for (x-10)(x-9)=-78 equation:

Simplifying
(x + -10)(x + -9) = -78

Reorder the terms:
(-10 + x)(x + -9) = -78

Reorder the terms:
(-10 + x)(-9 + x) = -78

Multiply (-10 + x) * (-9 + x)
(-10(-9 + x) + x(-9 + x)) = -78
((-9 * -10 + x * -10) + x(-9 + x)) = -78
((90 + -10x) + x(-9 + x)) = -78
(90 + -10x + (-9 * x + x * x)) = -78
(90 + -10x + (-9x + x2)) = -78

Combine like terms: -10x + -9x = -19x
(90 + -19x + x2) = -78

Solving
90 + -19x + x2 = -78

Solving for variable 'x'.

Reorder the terms:
90 + 78 + -19x + x2 = -78 + 78

Combine like terms: 90 + 78 = 168
168 + -19x + x2 = -78 + 78

Combine like terms: -78 + 78 = 0
168 + -19x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-168' to each side of the equation.
168 + -19x + -168 + x2 = 0 + -168

Reorder the terms:
168 + -168 + -19x + x2 = 0 + -168

Combine like terms: 168 + -168 = 0
0 + -19x + x2 = 0 + -168
-19x + x2 = 0 + -168

Combine like terms: 0 + -168 = -168
-19x + x2 = -168

The x term is -19x.  Take half its coefficient (-9.5).
Square it (90.25) and add it to both sides.

Add '90.25' to each side of the equation.
-19x + 90.25 + x2 = -168 + 90.25

Reorder the terms:
90.25 + -19x + x2 = -168 + 90.25

Combine like terms: -168 + 90.25 = -77.75
90.25 + -19x + x2 = -77.75

Factor a perfect square on the left side:
(x + -9.5)(x + -9.5) = -77.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.