# What is the standard form of  y=(x - 8) (x + 10) ?

Jul 23, 2016

Check out the explanation.

#### Explanation:

I would highly recommend using the FOIL method, a mnemonic device that I was taught in my Algebra class. It's simple and very easy to learn and memorize.

So first, let's start off with the equation:

$y = \left(x - 8\right) \left(x + 10\right)$

Using the FOIL method, I will:

• Multiply the $x$ in the first set of parenthesis by the $x$ in the second set of parenthesis

${x}^{2}$

• Multiply the $x$ in the first set of parenthesis by the $10$ in the second set of parenthesis

$+ 10 x$

• Multiply the $- 8$ in the first set of parenthesis by the $x$ in the second set of parenthesis

$- 8 x$

• Multiply the $- 8$ in the first set of parenthesis by the $10$ in the second set of parenthesis.

$- 80$

Now let's combine them all together into one equation:

$y = {x}^{2} + 10 x - 8 x - 80$

And let's simplify that equation by combining like terms (in this case it's the two numbers that share $x$ as a variable, $10 x$ and $- 8 x$). To combine them, all I did was subtract $10 x$ and $- 8 x$:

• $y = {x}^{2} + 2 x - 80$