SOLUTION: Solve each system by substitution x/6 + y/10= 3 5x/16 - 3y/16= 15/8 / are fractions. Sorry. I know the answer is 12,10. Can you show me how to get that?

Algebra ->  Equations -> SOLUTION: Solve each system by substitution x/6 + y/10= 3 5x/16 - 3y/16= 15/8 / are fractions. Sorry. I know the answer is 12,10. Can you show me how to get that?      Log On


   



Question 329179: Solve each system by substitution
x/6 + y/10= 3
5x/16 - 3y/16= 15/8
/ are fractions. Sorry.
I know the answer is 12,10. Can you show me how to get that?

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Solve each system by substitution
x%2F6+%2B+y%2F10+=+3
:
%285x%29%2F16+-+%283y%29%2F16+=+15%2F8
:
Get rid of those annoying fractions
:
Mult 1st equation by 30, results:
5x + 3y = 90
3y = 90 - 5x
divide thru by 3
y = 30 - 5%2F3x; use this for substitution
:
Mult 2nd equation by 16, results
5x - 3y = 2(15)
5x - 3y = 30
Substitute for y
5x - 3(30 - 5%2F3x) = 30
5x - 90 + 5x = 30
5x + 5x = 30 + 90
10x = 120
x = 12
:
Find y using eq: 5x - 3y = 30; replace x with 12
5(12) - 3y = 30
60 - 3y = 30
-3y = 30 - 60
-3y = -30
y = +10
:
:
Check solutions in the first original equation
x%2F6+%2B+y%2F10+=+3
12%2F6+%2B+10%2F10+=+3