Answer:
The answer is 313.
Step-by-step explanation:
You have to substitite the values of x and y into the expressions :
[tex]5 + 7(3x + y)[/tex]
[tex]let \: x = 12,y = 8[/tex]
[tex]5 + 7(3
\times 12 + 8)[/tex]
[tex] = 5 + 7(36 + 8)[/tex]
[tex] = 5 + 7(44)[/tex]
[tex] = 5 + 308[/tex]
[tex] = 313[/tex]