-x^2+90x-1400=0

Solution for -x^2+90x-1400=0 equation:

Simplifying
-1x2 + 90x + -1400 = 0

Reorder the terms:
-1400 + 90x + -1x2 = 0

Solving
-1400 + 90x + -1x2 = 0

Solving for variable 'x'.

Factor a trinomial.
(-70 + x)(20 + -1x) = 0

Subproblem 1
Set the factor '(-70 + x)' equal to zero and attempt to solve:

Simplifying
-70 + x = 0

Solving
-70 + x = 0

Move all terms containing x to the left, all other terms to the right.

Add '70' to each side of the equation.
-70 + 70 + x = 0 + 70

Combine like terms: -70 + 70 = 0
0 + x = 0 + 70
x = 0 + 70

Combine like terms: 0 + 70 = 70
x = 70

Simplifying
x = 70
Subproblem 2
Set the factor '(20 + -1x)' equal to zero and attempt to solve:

Simplifying
20 + -1x = 0

Solving
20 + -1x = 0

Move all terms containing x to the left, all other terms to the right.

Add '-20' to each side of the equation.
20 + -20 + -1x = 0 + -20

Combine like terms: 20 + -20 = 0
0 + -1x = 0 + -20
-1x = 0 + -20

Combine like terms: 0 + -20 = -20
-1x = -20

Divide each side by '-1'.
x = 20

Simplifying
x = 20
Solution
x = {70, 20}