Question

Need help graphing this linear equation.

5S+10L=70

Answer 1

Okay, I want you to pay close attention, because graphing lines might make up a huge chunk of your maths-related work in the days to come, you ready?

Answer 2

yes

Answer 3

Graphing lines always involves finding two points on the Cartesian Plane, and then just connecting those two points. Catch me so far?

Answer 4

yes

Answer 5

The easiest way to do this is to get what's called the intercepts. But more on that later. Let's draw the coordinate system, shall we? (You can do a much better job at drawing than I can, but I'll try my best)

Answer 6

Okay, the horizontal line has to correspond to one of your variables, and the vertical line to the other. Which is the horizontal, S or L? (I really don't know, we usually work with x and y, with x corresponding to the horizontal)

Answer 7

I believe s is x and L is y

Answer 8

Okay, so let's just make that clear...

Answer 9

Let's rewrite your equation...
5S + 10L = 70

Answer 10

Now, "listen" well, the next part is the trickiest part (though of course, not that tricky at all).
When S = 0, what value does L take?

Answer 11

10?

Answer 12

No, see, when you let S = 0, you substitute 0 for S...
5(0) + 10L = 70
And then solve for L.

Answer 13

7?

Answer 14

Yes. Very good. So, you plot that point (remembering that S is x and L is y)
(0 , 7)

Answer 15

Now, what if we let L = 0 instead, what becomes of S?

Answer 16

14?

Answer 17

Yes. So we plot that point, (but this time, it's L that's zero, so it's the second coordinate that's zero)
Plot the point (14 , 0)
which would right about be here...

Answer 18

Can you predict the next step? The next step is the last, the easiest, and the most rewarding...

Answer 19

drawing the line?

Answer 20

Yeah. Connect the dots ^.^

Answer 21

That was really easy :) thank you.

Answer 22

No problem.