Question

use substitution to solve
3X+Y=6
4X+2Y=8

Answer 1

Hi there!
Welcome To OpenStudy
This question belongs in the math section however i'll help! ^_^
Ok any ideas on where to start? :-)

Answer 2

Hi Thank you,
well no really...

Answer 3

No worries :-)
Ok, so are you fimiliar with the substitution method?

Answer 4

I'm trying to understanding it

Answer 5

Alright,
3X+Y=6
Do you know how to isolate y?

Answer 6

I will do Y=3X+6?

Answer 7

almost!
y=-3x+6
Remember the we subtracted 3x from both sides...
Now we have:
y=-3x+6 <---equation 1
4X+2Y=8 <---equation 2
We know the value of y so we can plug equation 1 into equation 2
4x+2(-3x+6)=8
try solving for x

Answer 8

Thank you, may sense
4X-6X+6=8
-2X=2
X=1

Answer 9

Is that correct?

Answer 10

Not right...
4x+2(-3x+6)=8
4x-6x+12=8
Remember that you need to distribute the 2
4x-6x+12=8
solve for x from here

Answer 11

-2X+12=8
-2X=-4
X=-4 ?

Answer 12

A negative number divided by a negative number becomes positive

Answer 13

-2x+12=8
subtract 12 from both sides

Answer 14

@UsukiDoll reguardless the answer is wrong.

Answer 15

:(

Answer 16

At least the user tried...geez

Answer 17

Ok let me try again

Answer 18

Keep trying! :)
And @UsukiDoll I think the user would rather get proper help, would you like me to say the answer is correct when it isn't?
Anyways @moyabote
-2x+12=8
subtract 12 from both sides

Answer 19

And ugh
8-12 is -4 which I saw earlier
4x -6x is -2x which I saw earlier as well it was almost right but the division part was wrong.

Answer 20

X=2 ?

Answer 21

Yep perfect :)

Answer 22

Now we take x=2 and plug it into equation 1 :)
y=-3(2)+6
now just solve for y :) and we're done B)

Answer 23

Thank you so much, by the way, I'm a concern mother trying to understand so I can explain to my child, but I'm from Colombia and I finished high school in 1990, and the method is very different. Thank you for your help, I really appreciate it :)

Answer 24

No problem hope you continue to use the site :D
And you can also help your child by using this
https://www.mathsisfun.com/algebra/substitution.html
its more visual

Answer 25

thank you so much

Answer 26

yw ^_^