How do you solve the system #2x + y = 0# and #3x - y = - 10#?

Question

2415 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2015-05-16T17:16:35

One easy way to think this problem is by isolating one variable in one equation and substitute the value you find in the second equation, as follows:

For example, let's isolate #y# in the first equation:

#y=-2x#

Now, let's just substitute this value we found in the second equation:

#3x-(-2x)=-10#
#5x=-10#
#x=(-10/5)=-2#

Now, we know #x=-2# and we can complete the value of #y#, because we already know that #y=-2x#

Then, #y=-2(-2)#.
#y=4#.