# What is the standard form of y= (4x-5)(x-4) ?

Jan 8, 2016

$y = 4 {x}^{2} - 21 x + 20$

#### Explanation:

You can use the FOIL mnemonic to help multiply this out:

$y = \left(4 x - 5\right) \left(x - 4\right)$

$= \stackrel{\text{First" overbrace((4x*x)) + stackrel "Outside" overbrace((4x*-4)) + stackrel "Inside" overbrace((-5*x)) + stackrel "Last}}{\overbrace{\left(- 5 \cdot - 4\right)}}$

$= 4 {x}^{2} - 16 x - 5 x + 20$

$= 4 {x}^{2} - 21 x + 20$

Standard form puts the powers of $x$ in descending order.