Question

The sum of two numbers is -3 and their product is -10. What are the two number?

Answer 1

Let the number be x and y.

The sum is -3:

x + y = -3

Their product is -10:

xy = -10

.

x + y = -3 ------------------ [ 1 ]

xy = -10 ------------------ [ 2 ]

.

From [ 1 ]

x + y = -3

x = - 3 - y ------------------ Substitute in [ 2 ]

.

xy = -10

( -3 -y) y = -10

-3y - y² = -10

y² + 3y - 10 = 0

(y + 5)(y - 2) = 0

y = -5 or y = 2

.

If y = -5

x = - 3 - ( - 5) = 2

if y = 2

x = - 3 - ( 2 ) = -5

.

Answer: The 2 numbers are 2 and -5