Question

Twice a number minus another number is 8. Their sum is -2. Find the numbers.

Answer 1

2 and -4

EXPLANATION :

Let x = number

and

y = other number

Twice the number (2x)

minus another number (y) is 8

That will be :

2x - y = 8

Their sum is -2, so :

x + y = -2

We now have two equations and two unknowns.

`\begin{gathered} 2x-y=8 \\ x+y=-2 \end{gathered}`

Add the two equations to eliminate the variable y :

`\begin{gathered} (2x+x)+(-y+y)=8+(-2) \\ 3x=6 \\ x=(6)/(3)=2 \end{gathered}`

Substitute x = 2 to the second equation :

`\begin{gathered} x+y=-2 \\ 2+y=-2 \\ y=-2-2 \\ y=-4 \end{gathered}`

So the numbers are 2 and -4