What times what equals -90 but adds up to -5?

Answer 1

-95

Answer 2

The factor pairs of -90 are (-90, 1) (-45, 2) (-30, 3) (-18, 5) (-15, 6) (-10, 9)(90, -1) (45, -2) (30, -3) (18, -5) (15, -6) (10, -9)

None of them add up to 5.

Alternate answer with non-integer solution:

The question can be represented by two simultaneous equations:

• x + y = -5
• x * y = -90

Solving the first for x gives you x = -y - 5

Substituting for x in in the other equation: (-y -5) * y = -90 gives you -y^2 -5y = -90

Moving things around gives the quadratic equation: y^2 + 5y - 90 = 0 which evaluates to either of:

Y = (-5 - sqrt(385)/2 which solves to -12.310708435 and more digits

Y = (-5 + sqrt(385)/2 which solves to 7.310708435 and more digits

Plugging in Y into the two equations gives you the same two values so the solution is

• -12.310708435 + 7.310708435 = -5 or close to it
• -12.310708435 * 7.310708435 = -90 or close to it