Solve by substitution: 2x+y=0
x-3y=-7
please help.

Question

Solve by substitution: 2x+y=0
                                     x-3y=-7
please help.

anonymous · Answer

Please help?

anonymous · Answer

substitution requires you to solve for one variable in one equation, and substitute your results into the other equation.

for example, if you solve the first equation for 'y' you'll obtain:  y = -2x.  then you replaced 'y' with '-2x' in the other equation and solve for x.

anonymous · Answer

replace*

anonymous · Answer

So How do I break it down to actually show my math? This is where I get stuck Lol. I understand what you're saying. It's just showing my work is where I get in trouble.

anonymous · Answer

2x+y=0....1)
x-3y=-7....2)

y=-2x...3)
therefore: substitute 3) into 2)
x-3(-2x)=-7
x+6x=-7
7x=-7
x=-1

therefore:y=-2x
  y=-2(-1)
y=2

anonymous · Answer

So y =2 got that. This makes sense now. Thank you so much.