Help with finding formula to this problem?

system

x + y = - 12

x - y = - 2

--------------- add

2x = -14

x = -14/2

x = -7;

y = -12+7

y = -5

x = -7; y = -5

Bye

gilvi

You could use numerous strategies. The two most common are substitution and combination. I will show you combination and leave the substitution method to you.

If we have:

x+y=-12

x-y=-2

And we combine them, we see that the y terms cancel out and that:

2x=-14

So that x=-7.

Now plug this into either equation to find that y=-5, and check the solutions as you did.

THe substitution method would involve noting that, for example, x=-12-y from the first equation and plugging this into the second equation and solving for y....

Any method gets the same result.