184k views
4 votes
Substiute
y=3x-15
4x+2y=22

1 Answer

4 votes
You can solve it by replacing the Y in the 2nd equation with the solved Y in the first.

4x + 2(3x-15)= 22

that should give you...

4x + 6x - 30 = 22

then combine like terms...

10x - 30 = 22

now we need to get X alone so add 30 to each side....

10x = 52

now divide both sides by 10..
X = 52\10

both are divisible by 2...

X = 26\5

you should be done unless you need Y as well then go back to the first and plug in what you found for X...

Y = 3(26÷5)- 15

and that should give you Y.

a 2nd method you can make your own answer by making x = 0 ..

Y= 3(0) -15

Y= -15

now put that in the 2nd for Y...

4x+ 2(-15) = 22...

4x-30= 22

add 30 to both sides..

4x = 52

divide by 4....

X = 13

now take this to the first for x...

Y= 3(15) - 15

Y = 30

you can check your work by plugging in the two on top and see if the final is the same..

30 = 3(15) - 15

the 2nd way is faster though of course..

anyway X= 13 Y= 30
User CalculatingKraken
by
8.0k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories