Question

I'm trying to find the oredered pair for 2x-y=8 and 9x-4=37

Answer 1

hello, @x95b20
\(\Huge \mathcal{\text{Welcome To OpenStudy}\ddot\smile} \)

can you check the 2nd equation ?
is it 9x-4=37
or 9x-4y=37
or something else ?

Answer 2

it is 9x-4=37

Answer 3

if thats the case, then you can directly find 'x' from that equation!
first add 4 on both sides, what do u get ?

Answer 4

9x=41

Answer 5

so would x=4.5

Answer 6

yes, so x =41/9
i still think its 9x-4y=37
maybe there's typing mistake in your question ?

Answer 7

you're right! my typo...sorry

Answer 8

9x=41
x=41/9 = 4.555 is not an integer solution
whereas with 9x-4y=37
we get integers
,,,,good! no problem :)

Answer 9

so, do u know about elimination method ? or substitution method ??

Answer 10

am trying to learn the substitution method..

Answer 11

good, so
can you isolate 'y' from
2x-y =8 ??
y=.... ?

Answer 12

I think I have to get rid of the 2...
So would I subract 2 from each side?

Answer 13

no, to isolate 'y' , you need to get rid of entire 2x term with y
so, easier thing to do will be add 'y' to both sides first and then subtract 8 from both sides....try ?

Answer 14

2x-y+y=8
2x=16?

Answer 15

2x=0 because the subraction got rid of the 8

Answer 16

oh, but when you add 'y' to BOTH SIDES, you add it to RIGHT side too!
so,
2x-y +y = 8+ y
gives
2x = 8+y
got this ??
now you can subtract 8 from BOTH sides...

Answer 17

yes.. now I need to subract 8 from each side...

Answer 18

correct, do that and tell me what u get ?

Answer 19

-6x=0y

Answer 20

oh, you CANNOT combine 2x and -8 to get -6x or anything, they are NOT like terms...only like terms can be combined!

so,
2x-8 = 8-8+y
gives
2x-8 = 0+y
or
y= 2x-8
clear till here ?

Answer 21

since 8 doesn't have an x I cannot subract it then

Answer 22

correct, 8 doesn't have x
but you can subtract 8, just cannot combine it with 2x there, because as you said, 8 doesn't have x

Answer 23

ok

Answer 24

so, now can we go further with the problem?

Answer 25

we can divide it by 2 so x=4?

Answer 26

in y= 2x-8 ?
there's still a 'y' there...
thats where 2nd equation comes into picture! :)
we got y as 2x-8, now we plug this in 2nd equation for 'y'

9x-4y=37
9x-4 (2x-8) =37
got this step ?

Answer 27

yes

Answer 28

Im plugging in the first y where this y is

Answer 29

now there's only 'x' in the equation
9x-4 (2x-8) =37
can you get the value of 'x' ?

Answer 30

Can you explain the step?

Answer 31

ok, first we distribute the 4 inside the brackets...