Question

What the answer be? 1/3 or -2/3
for the value of x in:
15x-12y=13
30x+9y=4
Not sure, because both are possible answers. But only of the is correct.

Answer 1

so solve for x ...
you tried to set the y's up for elmination
that is...multiply the first equation by 9 and the second equation by 12
then add the equations together

Answer 2

so you have
the following equation to solve:
\[(9 \cdot 15+12 \cdot 30)x+(9 \cdot -12+12 \cdot 9)y=(9 \cdot 13+12 \cdot 4)\]

Answer 3

Thanks. :)