Question

How do you solve by substitution and graph with the problem: Eq. 1: y=1/4x + 2 and Eq. 2: y=-4x + 36?

Answer 1

You need to equal the right hand side of the first equation with the right hand side of the second equation.

Answer 2

You're told that\[y=\frac{1}{4}x+2\]and\[y=-4x+36.\]Could we then say that\[\frac{1}{4}x+2=-4x+36\]and solve for \(x\)?

Answer 3

And solve for x

Answer 4

And then you can find the x-intercept and y-intercept of each line.

Answer 5

I tried to solve for x, but i ended up with a really complicated fraction

Answer 6

make x = 0 and solve for y, to find the y-incercept

Answer 7

Wha did you get?

Answer 8

What if you multiply both sides by \(4\)?\[\frac{1}{4}x+2=-4x+36,\]\[x+8=-16x+144?\]Does that help with the fraction?

Answer 9

She multiply both sides of the equation by 4

Answer 10

multiplied

Answer 11

thank you so much!! Because i did that, i found out what x is. How would you solve by graphing?

Answer 12

You can follow this steps:
- substract 8 from both sides of the equation.
- add 16x to both sides of the equation.
- divide by 17 both sides of the equation.
And I think (if i'm not wrong) you get the value of x that satisfies the problem.

Answer 13

ahh.

Answer 14

Do you know how to graph a linear equation?

Answer 15

so you dont have to solve for y? you can solve for x to graph it?

Answer 16

Once you get the value of x, you can plug in to one of your equations and solve for y.

Answer 17

Did you get the value of y?

Answer 18

hold on, im still working the problem out

Answer 19

Did you get it?

Answer 20

to graph, do i have to start from 36 because the y intercept is 36 for y=-4x+36

Answer 21

yes if you let x = 0

Answer 22

so you have the coordinate (0,36)

Answer 23

You need the coordinates of another point on the line to graph it. You can get it with the x-intercept.

Answer 24

let y = 0, and solve for x.

Answer 25

so the x intercept would be 9 right?

Answer 26

Exactly!

Answer 27

So you have another coordinate (9,0)

Answer 28

You can do a line thar passes across those points.

Answer 29

and you can do the same for the other line.

Answer 30

pass, sorry

Answer 31

I'm not proud of my english =P

Answer 32

but your awsome at math :) if that makes you feel any better

Answer 33

haha thank you.

Answer 34

thank u :) this really helped alot

Answer 35

You're welcome =)