Question 419045
(A)~~~Area
{{{(4x)^2+56x+49}}}=
{{{(4x)^2+2*4x*7+7^2}}}=
{{{(4x+7)^2}}}
The side of the square is: 4x+7 
The perimeter is:
4(4x+7)=
16x+28
(B)~~~ when x=3
the perimeter is:
{{{16x+28=16*3+28=48+28=76}}}