How to Solve a System of Three Equations with Three Unknowns?

[mkelly18790]

How do I do:

a + b = 3
-b + c = 3
a + 2c = 10

 

[MarkFL]

I would begin by adding the first two equations, and then you have the 2X2 system:

$$a+c=6$$

$$a+2c=10$$

Now, try subtracting the first from the second to get $c$, then use the first along with the value for $c$ to find $a$, and then once you have $a$ and $c$, you can use either the first or second equation from the original system to find $b$. :D

What do you find?