SOLUTION: Question: solve each of the following systems by using either addition or substitution. If a unique solution does not exist, state wheter the system is dependent or inconsistant.

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Question 55842: Question: solve each of the following systems by using either addition or substitution. If a unique solution does not exist, state wheter the system is dependent or inconsistant. The problem is
10x+2y=7
y=5x+3
Can someone help to solve this?
Answer by Cintchr(481) About Me  (Show Source):
You can put this solution on YOUR website!
1. +10x%2B2y=7+
2. +y=5x%2B3+
In equation 2, get the 5x on the other side of the equation.
+-5x%2By=3+
Multiply each term by two
+-10x%2B2y+=+6+
now add the two equations....
+10x%2B2y=7+
+-10x%2B2y=6+
___________________
+4y+=13+
divide by 4
+y+=+13%2F4+

Substitute this back into any one of the equations.
+10x%2B2y=7+
+10x%2B2%2813%2F4%29=7+
Multiply
+10x+%2B+%2813%2F2%29+=+7+
subtract 13/2 from both sides
+10x+=+7+-+13%2F2+
Find common denomonators
+10x+=+14%2F2+-+13%2F2+
Combine like terms
+10x+=+1%2F2+
Divide by 10 ... or multiply by 1/10 .... it is the same thing.
+x+=+%281%2F2%29%281%2F10%29+
+x+=+1%2F20+

Your ordered pair is ....
( 13/4 , 1/20 )