Solve:
x+2y=13
4x+8y=-9

A. (3,5)
B. (-1,7)
C. No solutions
D. Infinitely many solutions

Question

Solve:
x+2y=13
4x+8y=-9

A. (3,5)
B. (-1,7)
C. No solutions
D. Infinitely many solutions

anonymous · Answer

I think it is C... But I don't know for sure if that's correct?

john_es · Answer

You are right ;).

anonymous · Answer

Are you sure?? I'm not very good at algebra so I don't have much confidence when I reach a solution....

john_es · Answer

You can solve it by reduction. Multiply the first equation by 4, then the system is now,
$$4x+8y=52\
4x+8y=-9$$
Now you see that it can not have any solution, because the same expression at the left side gives different numbers at the right side, so there is no solution.

anonymous · Answer

Thanks :) I had it right but I needed reassurance haha

john_es · Answer

You're welcome ;).