Question

What is the solution of the system of equations?

y = 3x + 7
y = x – 9


(–1, –10)


(–8, –17)


(–17, –8)


(4, 19)

Answer 1

Since both equations define y, they should be equivalent.

3x+7=x-9
2x+7=-9
2x=-16
x=-8

Plug x in
y=(-8)-9
y=-17

Final answer: (-8,-17)

Answer 2

the value of x=-8 and y=-17

Solution is (-8,-17)

Explanation:

`y = 3x + 7`

`y = x - 9`

Both the equation have y on the left hand side,

To solve both equation we set them equal and solve for x and y

Replace y with 3x+7 in second equation

`3x+7=x-9`

Subtract x on both sides

`2x+7=-9`

Subtract 7 on both sides

`2x=-16`

Divide by 2 on both sides

`x=-8`

Now plug in -8 for x in second equation

`y = x -9`

`y = -8 - 9=-17`

the value of x=-8 and y=-17

Solution is (-8,-17)