SOLUTION: i'm not quite sure how to solve this using substitution. x+5y=4 3x+15y=-1 Also, does the system have exactly one solution, or more? Thanks for helping me!

Algebra ->  Expressions-with-variables -> SOLUTION: i'm not quite sure how to solve this using substitution. x+5y=4 3x+15y=-1 Also, does the system have exactly one solution, or more? Thanks for helping me!      Log On


   

Question 5476: i'm not quite sure how to solve this using substitution.
x+5y=4
3x+15y=-1
Also, does the system have exactly one solution, or more?
Thanks for helping me!
Answer by Abbey(339) About Me  (Show Source):
You can put this solution on YOUR website!
take the first equation:
x+5y=5 and put it in terms of x by subtracting 5y from both sides:
x=5-5y
then use the second equation and substitute 5-5y in for x
3x+15y=-1
3(5-5y)+15y=-1
eliminate the parentheses, consolidate like terms and solve for y:
15-15y+15y=-1
15=-1
This is not a true statement, so no solution exists. (These are parallel lines and never cross, therefore they don't have an intersection)