SOLUTION: Please help, I'm very frustrated and don't understand how to solve linear systems with substitution. I have a lot of homework due tomorrow and don't understand what I'm supposed to

Question 192200This question is from textbook Algebra 1
: Please help, I'm very frustrated and don't understand how to solve linear systems with substitution. I have a lot of homework due tomorrow and don't understand what I'm supposed to do.
x-y=0
12x-5y=-21 This question is from textbook Algebra 1

Found 2 solutions by Alan3354, RAY100:
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
x-y=0
12x-5y=-21
----------
There's more than one way to do these, but substitution is the best for this one.
From eqn 1: x = y
Sub for x into the 2nd eqn
12y-5y=-21
7y = -21
y = -3
x = -3
That's all.
Answer by RAY100(1637) (Show Source): You can put this solution on YOUR website!
1) x-y=0
2) 12x-5y=-21
In substitution we use one eqn to establish a x to y relationship.
Then we substitute this relationship in the other eqn
for example from (1) we know x-y=0, therefore x=y
substituting into (2)
12 (y) -5y = -21
simplify
7y=-21
divide by 7
y=(-3)
substitute this in either (1) or (2) to find x
using (1) x-y=0
x-(-3) =0
y=(-3)
checking
(1) (-3)-(-3)=0 ok
(2) 12(-3) -5(-3) =-21
-36 +15 = -21 ok
RELATED QUESTIONS
Please help, I'm very frustrated and don't understand how to solve linear systems with... (answered by edjones)
Hello, I have recently started learning about the systems of linear equations. I... (answered by Earlsdon)
How do I find the area of a trapezoid? I don't understand so please help (answered by ewatrrr)
I don;t get this graphing thing at all! I have to solve the system of linear equations by (answered by ankor@dixie-net.com)
Hi im stuck in my algebra homework. I really dont understand how to solve linear systems... (answered by josgarithmetic)
I am having a lot of trouble with word problem questions. If someone could help me that... (answered by Edwin McCravy)
i need help with solving linear systems of equations... (answered by user_dude2008)
Hi, im Very confused on Linear Graphs anything to do with it. First here is a problem... (answered by checkley71,allamericangirl)
I have a question about linear systems using substitution. How do solve: x=6-4y and... (answered by Alan3354,stanbon)