Maths graph and lines and proportion

[Ella]

Really need help, thanks


Question1


Write down the coordinates of the point of intersection of the two lines whose equations are y= 5x-2 and y= -5x-2.


Questions2


P is directly proportional to the square root of Q. If P=6 when Q=100, find a formula expressing P in terms of Q.


I have the answers but I just don't understand how to get them, please help


Answers
1) (0,-2)
2) Q= (5P/3)squared

 

[mmm4444bot]

Really need help, thanks

Question1

Write down the coordinates of the point of intersection of the two lines whose equations are y= 5x-2 and y= -5x-2.

Questions2

P is directly proportional to the square root of Q. If P=6 when Q=100, find a formula expressing P in terms of Q.

I have the answers but I just don't understand how to get them, please help

Answers

1) (0,-2)

2) Q= (5P/3)squared

Welcome to the boards, Ella.

This is a tutoring web site. We ask that you follow the forum guidelines. Please read this summary page, before posting again. (Links to the complete guidelines and forum rules appear near the bottom on that page.)

Thank you! :cool:

 

[JeffM]

Really need help, thanks


Question1


Write down the coordinates of the point of intersection of the two lines whose equations are y= 5x-2 and y= -5x-2.


Questions2


P is directly proportional to the square root of Q. If P=6 when Q=100, find a formula expressing P in terms of Q.


I have the answers but I just don't understand how to get them, please help


Answers
1) (0,-2)
2) Q= (5P/3)squared

Ella

Please read READ BEFORE POSTING at http://www.freemathhelp.com/forum/threads/54003-Read-Before-Posting before posting again.

You will see there that we do not like more than one problem per thread. We also provide help, not answers.

Now with respect to your first problem there are at least two ways to solve it. One way is to graph both lines carefully. Can you do that? Now at what point do they intersect? The other way is algebraically. Do you know how to solve two linear equations in two unknowns? How would you start? Do you think substitution or elimination is easier in this case?

 

[Quaid]

P is directly proportional to the square root of Q. If P=6 when Q=100, find a formula expressing P in terms of Q.

Answer

Q = (5P/3)squared

Hi Ella:

Again, this answer is wrong. The instruction (highlighted in red above) requires a formula of the form

P = <some expression containing the symbol Q>

The formula that you posted is "backwards".


May I ask what you're doing? Are you a student? Is this homework? Are you a parent, trying to help a child with a placement exam?

The questions that you've posted cover several weeks of classroom instruction. (The volunteers at this site do not have time to teach classroom material on the boards.)

Do you need links to online lessons, covering these topics? The more we know about your situation, the better we can respond.