Question

Express as a simplified polynomial:

(4a + 5)^2

Answer 1

\[(4a+5)^2=(4a+5)(4a+5)=16a^2+20a+20a+25\]
\[=16a^2+40a+25\]

Answer 2

or you can use
\[(a+b)^2=a^2+2ab+b^2\] with
\[a=4a,b=5\] it amounts to the same thing