Question

How would you solve this system of equations: 0.5x-4=y and -2.5x-2.5=y ?

Answer 1

Do you need to do it by graphing?

Answer 2

Yes. I'm getting confused by finding these equations slope & y intercept, and because of the decimals.

Answer 3

On these it might be better to do the x and y intercept method

Answer 4

Oh. Well, The x on the first one would be 0.5 and the x on the second one would be 2.5, I think?

Answer 5

To get the x intercept substitute 0 in for y and solve for x

0.5x-4=y
.5x-4=0
.5x=4
x=8

so the x intercept for that one would be (8,0)

Answer 6

How did you get that?

Answer 7

I put 0 where y is and solved for x

Answer 8

Thats how you get the x intercept

Answer 9

I'm confused. I know it works out, 0.5*8-4=0 , but how do you work that out to get 8?

Answer 10

Alright we have 0.5x-4=y

put 0 where y is

.5x-4=0

add 4 to both sides

.5x=4

divide both sides by .5

x=8

Answer 11

And thats the x intercept so (8,0)

Answer 12

Ok, I get it. So, on the second equation, the x intercept would be (5,0)

Answer 13

Not quite, but lets finish the first one first i dont wanna get mixed up lol.

To get the y intercept you do the same thing except instead of putting 0 in for y, you put it in for x.

0.5x-4=y
.5(0)-4=y
-4=y

so y intercept would be (0,-4) now you can graph that line using the x and y intercept

Answer 14

Haha. :) Ok, I get the y intercept part. Thats pretty simple. But the x intercept is a lil more confusing. I think the y intercept on the second equation would be -2.5 because -2.5(0)-2.5= -2.5 but I don't get the x intercept part

Answer 15

Yep, so you have one line plotted with the x and y intercept (0,-4) and (8,0)

You're right on the next ones y intercept so (0,-2.5)

x intercept would be
-2.5x-2.5=y
-2.5x-2.5=0

what do you get when you solve that for x?

Answer 16

I don't know. How do you solve for it?

Answer 17

Its a simple equation, first add 2.5 to both sides to get

-2.5x=2.5

then divide both sides by -2.5

x=-1

Answer 18

Oh, I understand. Thank you! Your a genius. :)

Answer 19

It would be (-1,0) right?

Answer 20

Yep, now find where they intersect to get your solution.
You're welcome