please help me out (:

find the x coordinate when you solve x-y=30
-x+4y=15

a.15
b.-5
c.30
d.45

Question

please help me out (:

find the x coordinate when you solve x-y=30
                                                         -x+4y=15

a.15
b.-5
c.30
d.45

anonymous · Answer

set the first equation to y so
y=x-30
 and plug it into your second equation so
-x+4(x-30)=15
and simplify

-x+4x-120=15
3x=135
x=45

lalaly · Answer

add both equations .. the x cancels
3y=45
y=15
substitute in any one of the equations
x-15=30
x=15+30 = 45

anonymous · Answer

is this the one you were talking about lalaly?

lalaly · Answer

no, i meant the one with the even consecutive numbers

anonymous · Answer

what was the answer?

lalaly · Answer

they didnt explain it to u right, and the answer was 50

anonymous · Answer

can you explain how i get 50 please?

lalaly · Answer

can u post the question again xD without the choices only the question

anonymous · Answer

why was it deleted...?

lalaly · Answer

i think it was 
the sum of three consecutive even numbers equals 156. what is the least of these numbers?