#### Answer

(2, 1, -3)

#### Work Step by Step

In order to solve systems of three linear equations, we multiply the first and second equation by values that will cancel out a variable when they are added. Thus, we multiply the first equation by 1 and the second equation by 2 and add to obtain:
$10x + 3y = 23 $
We now multiply the first and third equation by values that will cancel out a variable when they are added. Thus, we multiply the first equation by -2 and the third equation by one and add to obtain:
$ -6x +5y =-7 $
Plugging $x = -.3y + 2.3$ into this equation, we obtain:
$6.8y -13.8 = -7 \\ y =1 $
Now, we plug this value into one of the equations that only has x and y in them to find:
$ x = 2$
Finally, we plug the values of x and y into the first equation listed in the book to find:
$ z = -3$