Expert: Paul Klarreich - 10/28/2008

Question
I know how to graph this question but I'm not sure how to solve algebraically.

Solve the following system of equations both graphically and algebraically.  show all work.

y=-x^2+5x and y=-5+x



Thanks.

D

Following is the reason:

What I received for the problem was y=-x^+5x and y=-5+x.

There should be something after the ^ and before the + if there is suppose to be an exponet here.  If it is x^2, the ^2 can be done as alt-253, which gives ².



Expert: Scott A Wilson


Answer
Questioner:   Debbi
Category:  Advanced Math
Private:  No
 
Subject:  ALGEBRA
Question:  I know how to graph this question but I'm not sure how to solve algebraically.

Solve the following system of equations both graphically and algebraically.  show all work.

y=-x^2+5x and y=-5+x


Thanks.

D

Following is the reason:

What I received for the problem was y=-x^+5x and y=-5+x.

There should be something after the ^ and before the + if there is suppose to be an exponet here.  If it is x^2, the ^2 can be done as alt-253, which gives ².



Expert: Scott A Wilson
................................
Hi, Debbi,

I am not sure how I got this, since I am not Wilson, but anyway, here goes.

You solve a NON-linear system by substitution.

y = - x^2 + 5x  (A)
y = -5 + x      (B)

Subst  B into A:

-5 + x = - x^2 + 5x

Now this is just a quadratic.

x^2 - 4x - 5 = 0

Now solve this, take each root as x, and use it to find y = -x + 5.

That should do it.

And go ahead and send me questions, but don't mess around with that alt-253 stuff.  I have no idea what it is.