I do one for you but you have to promise me to try the other three.

These are your equations,

There five ways to solve these problem.

I will only mention two which I believe you should know: addition method, substitution method.

**Addition method**
Add the two equations, note that

,

,

Thus,

from here divide both sides by three,

, thus,

*The entire purpose of the addition method is when you add your equation you eliminate one of the variables and are left with one*.

**Substitution method**
Solve and equation for any variable, i.e. first equation for 'x' thus,

Now substitute that into the second equation,

, you substituted 'x' for 'y' and hence eliminated a variable.

Open parantheses,

Subtract 66 and combine 'y' to get,

divide by (-3) to get,

thus,