Question

will give medal and fan best answerer

Given the system of equations, what is the y-coordinate of the solution? (this is a matrix problem btw)

5x - 4y = 7
x = 5 - y

36/7
36/23
18/23

Answer 1

In this situation, you can do two things:
change both equations to equal to y and then set them equal to each other or use a scalar and subtract/add the equations.
In this case, I like to use the scalar as fractions are really messy.

Answer 2

Solve for x and then substitute the x-value into one of the equations(either is fine) to find the y-value.

Answer 3

@Grazes you see this is what confuses me i understand that method but it gives you three correct answers for y witch one would it be?

Answer 4

What. Hang on. I'll do it.

Answer 5

I don't know what you're talking about but y should be 2 and there should only be one value of y that is true for an x in a system of equations.

Answer 6

thanks for trying @Grazes

Answer 7

@arilove1d can you please help

Answer 8

y =2

STEP 1: Multiply second equation by -5.
After multiplying we have the following system:
5x−4y−5x−5y=7=−25
STEP 2: add the two equations together to eliminate x from the system.
−9y=−18
STEP 3: find y
y=2
STEP 4: substitute the value for y into the original equation to solve for x.
5x−4(2)=7
x=3

Answer 9

@arilove1d ya thats what @Grazes said but it gives me 3 answer for the y coordinate 36/7
36/3 18/23

Answer 10

Hmmm i know its not the last one that would give you an decimal

Answer 11

@arilove1d ya this confuses me majorly.... since when was math hard :/

Answer 12

@csscgirl THIS CONFUSES ME!!! pleasehelp

Answer 13

@csscgirl it is a matrix

Answer 14

the y is 2, so idk sorry... but... just a sec.

Answer 15

or 25/9... idk

Answer 16

its okay thanks for your help @csscgirl i know ts super confusing...

Answer 17

yw.... umm... @Mertsj

Answer 18

@Mertsj do you understand

Answer 19

\[5(5-y)-4y=7\]
\[25-5y-4y=7\]
\[25-9y=7\]
\[-9y=-18\]
\[y=2\]

Answer 20

The solution is (3,2)
http://www.wolframalpha.com/input/?i=Solve+this+system%3A+5x+-+4y+%3D+7++%3B+++++++++++++++++++x+%3D+5+-+y

Answer 21

@mertj i literally copied this strait from my math website and pasted it and there are three option i know that y=2 and x=3 but i dont understand how t would equal any of the options... its called matrices the lesson im on if that helps

Answer 22

Give me a link to the math website and let me look at it.

Answer 23

https://ortrail.owschools.com/owsoo/studentAssignment/index?eh=344591183

Answer 24

That's only a login page.

Answer 25

I can't see it unless you give me you user name and password.

Answer 26

I don't think you got the list of answers that goes with that question.

Answer 27

@Mertsj

Answer 28

i hate this math class