Answer:
The correct graph is attached to the answer.
The amount of fruit syrup Rex added is: 3 liters
and the amount of water he added is: 4 liters.
Explanation:
x denote the amount of fruit syrup added and y denote the amount of water added.
It is given that:
Three times the number of liters of water he mixed was 6 more than twice the number of liters of syrup he mixed.
i.e. the equation that satisfies this condition is:
![3y=2x+6\\\\i.e.\\\\2x-3y=-6-----------(1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/prnlro73kk6e5is0s59gv3uq9owbj9btjk.png)
i.e. the graph of this equation is a line that passes through (-3,0) and (0,2)
Also, The total number of liters of syrup and water he mixed was 7 liters.
Hence, the equation is:
![x+y=7------------(2)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/pzafe18tg0hdf63ii8jggc5ibh5jngg5cw.png)
i.e. the graph of this equality is a line that passes through (7,0) and (0,7)
Also, from equation (2) we have:
![x=7-y](https://img.qammunity.org/2019/formulas/mathematics/middle-school/njn8vt1y29jjfyhhv2t3gt60t41k1axwcw.png)
Now, on putting this value of x in terms of y in equation (1) we get:
![2(7-y)-3y=-6\\\\i.e.\\\\14-2y-3y=-6\\\\i.e.\\\\14-5y=-6\\\\i.e.\\\\14+6=5y\\\\i.e.\\\\5y=20\\\\i.e.\\\\y=4](https://img.qammunity.org/2019/formulas/mathematics/middle-school/8ef4liskf8ckkosunhv4tcr8td0ves72mf.png)
Also, on putting the value of y in equation (2) we get:
![x=3](https://img.qammunity.org/2019/formulas/mathematics/college/7ps1tadqt6n0r4c5twvavc795rj7e7v09l.png)
Hence, the solution to the system of linear equation is:
(3,4)