Question

2x - 5y = -1
x - 3y = -3
I need to find the solution by using subsitution method

Answer 1

As a first step, I would "solve for x" in the 2nd equation
x - 3y = -3

can you do that?

Answer 2

no, don't know where to begin

Answer 3

how do I subsitute for x when I am not sure what I am subsituting

Answer 4

When you get a chance
http://www.khanacademy.org/math/algebra/solving-linear-equations-and-inequalities/v/solving-for-a-variable

There are more that show how to solve equations.

Answer 5

But for this problem
x - 3y = -3
add +3y to both sides of the equation
x -3y +3y = -3 + 3y

Answer 6

you can simplify the left side: if you have 3 y's and take away 3 y's you are left with no y's

you get
x= -3 +3y

that means that you can replace x in the 1st equation with the equivalent
(-3+3y)

can you do that? what do you get?

Answer 7

yes I can.
I get 2(-3 +3y) - 5y = -1
-6 + 6y -5y = -1
-6 - y = -1
-6 + 6 -y = -1 + (-6)
-y= -5

Answer 8

I got x = -3 and y = -1

Answer 9

you have the right idea, but need to be more careful.
I get 2(-3 +3y) - 5y = -1
-6 + 6y -5y = -1

first notice you have 6 y take away 5 y how many y's do you get?

Answer 10

I only have one y left

Answer 11

for my answer I get x as -3 and y = -1

Answer 12

yes so
-6 + 6y -5y = -1
is
-6 +y = -1
now if you add +6 to both sides, what do you get?
+6-6+y= +6-1

Answer 13

y = 5

Answer 14

now use

x= -3 +3y

replace y with 5 and then figure out what x is

Answer 15

x = -3 + 3(5)
x = -3 + 15
x = 12

Answer 16

ok now test if your answer works
x=12, y =5 Does it work in the 1st equation?
2x - 5y = -1

Answer 17

2(12) -5(5) = -1
24 - 25 =-1
-1 = -1 yes I understand thank you so much this made it easier for me to work my other problems. Your a life saver

Answer 18

ok. The videos are helpful (for me anyways) if you need "inspiration"

Answer 19

great thanks