Solve for y in the 1st equation.
7x +2y=19
x-y=4

Question

turingtest · Answer

y=(1/2)(19-7x)

turingtest · Answer

is that all?

anonymous · Answer

I thought  Y= 19-7x/ 2?

anonymous · Answer

where did you get the 1/2 from?

turingtest · Answer

7x +2y=19
2y=19-7x
divide ALL by 2:
y=(19-7x)/2=(1/2)(19-7x)
if you just write
Y= 19-7x/ 2 
then you are not dividing the 19 by two, which you should be doing. Parentheses are important, keep track of them.

anonymous · Answer

sorry but I still don't understand how you got the 1/2

turingtest · Answer

do you understand that these two equations are the same?:
y=(19-7x)/2
y=(1/2)(19-7x)
In effect the WHOLE right side is being divided by 2 either way.

turingtest · Answer

here's another way to see it
2y=x
multiply both sides by (1/2):
y=(1/2)x=x/2
See? Dividing by 2 and multiplying by (1/2) is the same operation.

anonymous · Answer

nope

anonymous · Answer

2y|dw:1318343704749:dw|