Answer :

[tex]Put\ the\ value\ of\ a=3\ and\ b=5\ to\ the\ expression\ 8a+6(2b-7):\\\\8\cdot3+6\cdot(2\cdot5-7)=24+6\cdot(10-7)=24+6\cdot3=24+18=\boxed{42}\\\\Used\ PEMDAS\\\\Parenthesis\\Exponents\\Multiplication\\Division\\Addition\\Subtraction[/tex]
[tex]8\cdot3+6(2\cdot5-7)=\\ 24+6(10-7)=\\ 24+6\cdot3=\\ 24+18=\\ 42[/tex]