Solve the system by substitution method

1/2x+1/5y=-9/5 and 1/2x+3y=1

Question

Solve the system by substitution method

1/2x+1/5y=-9/5 and 1/2x+3y=1

anonymous · Answer

The answer choices i have are...
A. The solution set is ( , ) type an ordered pair.
B. There are infinetly many solutions
C.The solution is an empty set.

myininaya · Answer

do you want to get rid of those yucky fractions?
multiply one equation by 10 and the other by -10 then add the equations together

anonymous · Answer

i got the solution is an empty set is that correct? or did i go wrong somewhere?

myininaya · Answer

no i got a solution

anonymous · Answer

OH what did you get... i must have gone wrong somewhere

myininaya · Answer

multiply first equation by 10
multiply second equation by -10
then add the equations together

myininaya · Answer

10(1/2x+1/5y=-9/5)               5x+2y=-18
-10(1/2x+3y=1)                     -5x-30y=-10
                                               ______________
                                                 0x-28y=-28
                                                    -28y=-28

hope this helps

myininaya · Answer

so what does y=?

anonymous · Answer

y=-28 right? i think it is infinite solutions

myininaya · Answer

no we have -28y=-28
so y has to be 1

myininaya · Answer

-28(1)=-28 right?

myininaya · Answer

if y=1 and 5x+2y=-18,  then
5x+2(1)=-18  <- solve this equation for x

anonymous · Answer

I thought a negative times a postive was a postive?

myininaya · Answer

negative times a positive is certainly a negative

anonymous · Answer

oh my bad i always get them confused

anonymous · Answer

is the answer (-4,-1)?

anonymous · Answer

is the answer (-4,-1)?