Question

Substiute y=3x-15 4x+2y=22

Answer 1

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