# Graphs and equations

• Feb 12th 2009, 11:17 AM
Hannah95
Graphs and equations
Hi again !

a) A point on the line y=3x-4 has a x-coordinate of 50.
What is the y-coordinate of this point?

I did 3x50-4 and go 146 but I think its wrong! (Worried)

b) A point on the line y=3x-4 has a y-coordinate of 50.
What is the x-coordinate of this point?

I did 50+4 divided by 3 and got 18 but i think thats wrong too (Worried)

c) Is the point (-10, -34) on the line y=3x-4? Show how you know

Thankyou to anyone who can explain this to me !

Hannah (Wink)
• Feb 12th 2009, 11:40 AM
masters
Quote:

Originally Posted by Hannah95
Hi again !

a) A point on the line y=3x-4 has a x-coordinate of 50.
What is the y-coordinate of this point?

I did 3x50-4 and go 146 but I think its wrong! (Worried)

Hi Hannah,

Why would you think that? This is correct.

Quote:

Originally Posted by Hannah95
b) A point on the line y=3x-4 has a y-coordinate of 50.
What is the x-coordinate of this point?

I did 50+4 divided by 3 and got 18 but i think thats wrong too (Worried)

Come on Hannah, have a little faith. You are doing these correctly.

Quote:

Originally Posted by Hannah95
c) Is the point (-10, -34) on the line y=3x-4? Show how you know

Thankyou to anyone who can explain this to me !

Hannah (Wink)

On this one, just plug in the coordinates and see if the statement is true.

$-34=3(-10)-4$

$-34=-30-4$

$-34=-34$