How do you simplify the product (5x + 7)(7x + 3) and write it in standard form?

Mar 11, 2018

$35 {x}^{2} + 64 x + 21$

Explanation:

$\left(5 x + 7\right) \left(7 x + 3\right)$

Standard form means in the form $a {x}^{2} + b x + c$, where a, b, and c are the coefficients.

First, we distribute this expression:
$5 x \cdot 7 x = 35 {x}^{2}$

$7 \cdot 7 x = 49 x$

$5 x \cdot 3 = 15 x$

$7 \cdot 3 = 21$

Now when we put them all together we get:
$35 {x}^{2} + 49 x + 15 x + 21$

Now we simplify to get the final answer by adding $49 x$ and $15 x$:

$35 {x}^{2} + 64 x + 21$