The given expression is
[tex]\mleft(14x+14\mright)\mleft(2x+8\mright)[/tex]First, we use the distributive property
[tex]\begin{gathered} 14x\cdot2x+14x\cdot8+14\cdot2x+14\cdot8 \\ 28x^2+112x+28x+112 \end{gathered}[/tex]Then, we reduce like terms
[tex]28x^2+140x+112[/tex]Hence, the simplest expression is
[tex]28x^2+140x+112[/tex]