Substitution math?

Question

hey guys im stuck

what would i do

y=4x-1

y=2x-5

Answer 1

2x-5=4x-1

x= -2, y=-9

Answer 2

What he said is a perfectly legitimate way of doing it.

Another way is to solve the first for x:

y = 4x - 1

y + 1 = 4x

(y + 1) / 4 = x

Then plug that into the second:

y = (y + 1) / 2 - 5

y + 5 = (y + 1) / 2

2y + 10 = y + 1

y = - 9

Now that we know y we use it to solve x:

y = 4x - 1 (the thing you started out with, put -9 in for y)

-9 = 4x - 1

-8 = 4x

-2 = x