How do I find two variables in algebra with a given equation?

[GiTS]

Homework Statement

p=-x^2-2x+100 and p=8x+25, find p and x.

Homework Equations

The Attempt at a Solution

-x^2-2x+100=8x+125
-8x -8x
-100 -100
-x^2-10x=-75
x^2+10x=75
/10 /10
1/10x^2+x=75/10 i don't get how to get x alone on one side from here.

 

[DaxInvader]

Try (Ax^2) + Bx + C =0

then you know a formula to get x..

 

[HallsofIvy]

Homework Statement

p=-x^2-2x+100 and p=8x+25, find p and x.

Homework Equations

The Attempt at a Solution

-x^2-2x+100=8x+125
-8x -8x
-100 -100
-x^2-10x=-75
x^2+10x=75
/10 /10
1/10x^2+x=75/10 i don't get how to get x alone on one side from here.

Oh, c'mon! That's a quadratic equation. Factor if you can, or complete the square or use the quadratic formula. Oh, by the way, 125- 100= 25, not 75.

 

[GiTS]

Oh, c'mon! That's a quadratic equation. Factor if you can, or complete the square or use the quadratic formula. Oh, by the way, 125- 100= 25, not 75.

God I feel stupid. You'd think i'd recognize quadratic equations by now :P. I miswrote 125, supposed to be just 25. Thanks guys!

 

[DaxInvader]

No Preblem!


Problem solved :P