Question

What is the solution to the following system of equations?

y = −x2 − 5x − 4
y = −x2 + 9x − 18

1. (−1, −10)
2. (1, −10)
3. (−1, 10)
4. (1, 10)

Answer 1

`\ Start \ with \ the \ original \ equation`


`y=-x^2+9x-18`


`-x^2-5x-4=-x^2+9x-18`


`\ Solve \ for \ x`


`-x^2-5x-4=-x^2+9x-18`


`-5x-4=9x-18`
`\ Cancel \ -x2 \ on \ both \ sides`


`-4=9x-18+5x`
`\ Add \ 5x \ to \ both \ sides`


`-4=(9x+5x)-18`
`\ Gather \ like \ terms`


`-4=14x-18`


`-4+18=14x`
`\ Add \ 18 \ to \ both \ sides`


`14=14x`


`14 / 14=14x / 14`
`\ Divide \ by \ 14`


`x=1`
`Answer`


`\ Substitute \ x=1`


`y=-1x^2-5x-4`


`y=-12-5*1-4`


`y = -10`
`Answer`

___________________________


`x=1 y=-10`
`Solution`