SOLUTION: solve by substitution: 1/3x + 1/5y= 8/15 and 1/3x + 4y =70/3

Algebra ->  Expressions-with-variables -> SOLUTION: solve by substitution: 1/3x + 1/5y= 8/15 and 1/3x + 4y =70/3      Log On


   

Question 354515: solve by substitution: 1/3x + 1/5y= 8/15 and 1/3x + 4y =70/3
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!


First thing to do is to clear of fractions,

To clear 

expr%281%2F3%29x+%2B+expr%281%2F5%29y=+8%2F15

of fractions multiply through every term by LCD of 15

red%2815%29expr%281%2F3%29x+%2B+red%2815%29expr%281%2F5%29y=+red%2815%29expr%288%2F15%29

and get 

5x+%2B+3y+=+8

---

To clear 

expr%281%2F3%29x+%2B+4y+=70%2F3

of fractions multiply through every term by LCD of 3

red%283%29expr%281%2F3%29x+%2B+red%283%294y=+red%283%29expr%2870%2F3%29

and get 

x+%2B+12y+=+70

Then the system becomes easier to solve:

system%285x+%2B+3y+=+8%2C%0D%0Ax+%2B+12y+=+70%29

Can you solve that by yourself?  If not post again.

Solution: (x,y) = (-2,6)

Edwin