Chapter 4 - Quadratic Functions and Equations - Chapter Review - Page 270: 32

$(3x+5)^2$

Using $(a\pm b)^2=a^2\pm2ab+b^2$ or the square of a binomial, the given expression, $ 9x^2+30x+25 ,$ is equivalent to \begin{align*} & (3x)^2+2(15x)+(5)^2 \\&= (3x)^2+2(3x\cdot5)+(5)^2 \\&= (3x+5)^2 .\end{align*}