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

$y = - 8 {x}^{2} + 50 x - 42$

#### Explanation:

From the given equation
$y = \left(x + 7\right) \left(x + 1\right) - {\left(3 x - 7\right)}^{2}$

We start by expanding the right side using multiplication

$y = {x}^{2} + 8 x + 7 - \left(9 {x}^{2} - 42 x + 49\right)$

$y = {x}^{2} + 8 x + 7 - 9 {x}^{2} + 42 x - 49$

Simplify

$y = - 8 {x}^{2} + 50 x - 42$

graph{y=(x+7)(x+1)-(3x-7)^2[-80,80,-40,40]}

God bless....I hope the explanation is useful.