#1

find the point(s) of intersection of y=-x^2 +5x+8 and y=2x-10

Help me out, pit. I've been working on this question forever and can't figure this out.

EDIT: Can you actually do the question, and lay out the steps for me? thanks. <3.

Help me out, pit. I've been working on this question forever and can't figure this out.

EDIT: Can you actually do the question, and lay out the steps for me? thanks. <3.

*Last edited by tsoyguitar at Sep 30, 2009,*

#2

put 2x-10 in wherever the x appears in the other equation.

Solve for y, and then plug y into either equation and solve for x.

Solve for y, and then plug y into either equation and solve for x.

#3

y=y

-x^2 +5x + 8 =2x -10

-x^2 +3x+18=0

(-x-3)(x-6)

x=-3 x=6

Use the maths thread from now on though please.

EDIT: then ofcourse sub in the X values to your original y=

-x^2 +5x + 8 =2x -10

-x^2 +3x+18=0

(-x-3)(x-6)

x=-3 x=6

Use the maths thread from now on though please.

EDIT: then ofcourse sub in the X values to your original y=

*Last edited by Venice King at Sep 30, 2009,*

#5

just put into a graphing calculator and do 2nd trace, intersect..

#6

You could make them equal too each other and then solve for x?

Then substitute that into of one of the equations to get the y value and then get your co-ordinates.

I'm currently studying for a vector functions test, so graphical algebra isn't in my my mind right now lol

EDIT: Mr. Venice King has beaten me.

Then substitute that into of one of the equations to get the y value and then get your co-ordinates.

I'm currently studying for a vector functions test, so graphical algebra isn't in my my mind right now lol

EDIT: Mr. Venice King has beaten me.

*Last edited by Aussie_Warrior at Sep 30, 2009,*

#7

EDIT: Can you actually do the question, and lay out the steps for me? thanks. <3.

Dude.

#8

y=-x^2 +5x+8 and y=2x-10

You can substitute "2x-10" for "y" because they are equal. So 2x-10=x^2 +5x+8. Solve that and you will find x. Plug the number into one of the other equations and find y.

You can substitute "2x-10" for "y" because they are equal. So 2x-10=x^2 +5x+8. Solve that and you will find x. Plug the number into one of the other equations and find y.

#9

y=-x^2 +5x+8 and y=2x-10

You can substitute "2x-10" for "y" because they are equal. So 2x-10=x^2 +5x+8. Solve that and you will find x. Plug the number into one of the other equations and find y.

I said that like 10 minutes ago and did the steps for him but I don't even get thanks for these kinda things

#10

This is the latest thread I could find...

if x+y=7 and x^2-y^2=21 find the value of 2x+3y.

please :[

if x+y=7 and x^2-y^2=21 find the value of 2x+3y.

please :[