Question

Two numbers multiply to be -7 and add to be -6. What are the numbers?

Example; 2,3

Answer 1

Given:

Let the two numbers be x and y.

Two numbers multiply to be -7 and add to be -6.

This can be written in equation as,

`xy=-7` and

`x+y=-6`

Value of the two numbers:

Let us determine the value of the two numbers using substitution method.

Substituting
`y=-6-x` in the equation
`xy=-7`, we get;

`x(-6-x)=-7`

Simplifying, we get;

`-6x-x^2=-7`

`x^2+6x-7=0`

`(x+7)(x-1)=0`

`x=-7, 1`

Thus, the values of x are x = 1,-7

When x = 1 , the equation
`x+y=-6` becomes
`y=-7`

When x = -7, the equation
`x+y=-6` becomes
`y=1`

Therefore, the two numbers are 1 and -7