# How do you simplify (3+ 8x ) ( 9- 8x + 7x ^ { 2} ) ?

Mar 28, 2018

$56 {x}^{3}$ - $43 {x}^{2}$ + $48 x$ = 27

#### Explanation:

Multiply everything in the second bracket by everything in the first bracket then collect like terms.
$\left(3 + 8 x\right) \left(9 - 8 x + 7 {x}^{2}\right)$
first multiply the second bracket by 3;
$27 - 24 x + 21 {x}^{2}$
now multiply the second bracket by $8 x$;
$72 x - 64 {x}^{2} + 56 {x}^{3}$
I would write this all on one line as I did it like so:

$27 - 24 x + 21 {x}^{2} + 72 x - 64 {x}^{2} + 56 {x}^{3}$

Now collect like terms so all the terms without $x$ go together, all the terms with $x$, all the terms with ${x}^{2}$ and all the terms with ${x}^{3}$ etc

$27 + 48 x - 43 {x}^{2} + 56 {x}^{3}$

Then I rearranged it with the highest powers first (because I am a bit sad!)

$56 {x}^{3} - 43 {x}^{2} + 48 x + 27$