# What is the standard form of y= (3x-1)(7x-2)(x+1) ?

$21 {x}^{3} + 20 {x}^{2} + x + 2$

#### Explanation:

Given: $y = \left(3 x - 1\right) \left(7 x - 2\right) \left(x + 1\right)$
First, solve $\left(3 x - 1\right)$ and $\left(7 x - 1\right)$ by expanding them.
$\left(3 x - 1\right) \left(7 x - 2\right)$
$= 21 {x}^{2} - 6 x - 7 x + 2$
$= 21 {x}^{2} - x + 2$
Now,solve $\left(21 {x}^{2} - x + 2\right)$ and $\left(x + 1\right)$ by expanding them.
$\left(21 {x}^{2} - x + 2\right) \left(x + 1\right)$
$= 21 {x}^{3} + 21 {x}^{2} - {x}^{2} - x + 2 x + 2$
$= 21 {x}^{3} + 20 {x}^{2} + x + 2$