# Question #7d717

##### 3 Answers

#### Explanation:

Write a system that matches up with the information:

You can solve this with elimination. In this case, add them together to get rid of y.

Plug in to solve for y.

#### Explanation:

.

Let the numbers be

If we add the two equations we get:

Now, we can plug this into any of the equations to solve for

9 and 7

#### Explanation:

Well, what you have is, 2 equations in 2 unknowns. Which is enough to find a solution. There are a couple of ways to proceed, which no doubt you'll learn. For this example, probably the simplest is substitution.

Your 2 equations are:

From the second equation, we can say that:

...and now we *substitute* this value of a in the first equation:

...and now we can plug this back into the second equation, and solve for a:

GOOD LUCK