It is given that x is 5 less than the quotient of y and 3.
And given value of y is 18 .
So quotient of y and 3 is
[tex] \frac{18}{3} = 6 [/tex]
And 5 less than 6 =1
So we have y=18 and x=1
Given expression is
[tex] 3x+4(y+3) [/tex]
At x=1 and y=18, we will get
[tex] 3(1)+4(18+3) =3 + 4(21) [/tex]
[tex] = 3+84=87 [/tex]