Question

Please answer my first question

Answer 1

`\textit{area of a rectangle}\\\\ A=bh ~~ \begin{cases} b=base\\ h=height\\[-0.5em] \hrulefill\\ b=2x^2+5x+4\\ h=5x^3 \end{cases}\qquad \begin{array}{llll} \\\\\\ A~~ = ~~ \end{array} \begin{array}{cllll} 2x^2+5x+4\\\\ * ~~ 5x^3\\\cline{1-1} 10x^5+25x^4+20x^3 \end{array}`