Question 853494
Use the FOIL method,
{{{(4a+7)^2=(4a+7)(4a+7)}}}
First : {{{4a(4a)=16a^2}}}
Outer : {{{4a(7)=28a}}}
Inner : {{{7(4a)=28a}}}
Last : {{{7(7)=49}}}
{{{(4a+7)^2=16a^2+28a+28a+49}}}
{{{(4a+7)^2=16a^2+56a+49}}}