# How do you multiply (5y - 3) ( 5y - 8)?

Nov 4, 2017

See explanation.

#### Explanation:

To multiply 2 polynomials you have to multiply each term in one of the polynomials by each term of the other and then reduce the like terms:

## $= 25 {y}^{2} - 40 y - 15 y + 24 = 25 {y}^{2} - 55 y + 24$

Nov 4, 2017

$25 {y}^{2} - 55 y + 24$

#### Explanation:

color(blue)((5y-3)(5y-8)

We can use the FOIL method to solve this

Now multiply the firsts

$\rightarrow 5 y \times 5 y = 25 {y}^{2}$

Now multiply the outers

$\rightarrow 5 y \times - 8 = - 40 y$

Now multiply the inners

$\rightarrow - 3 \times 5 y = - 15 y$

Now multiply the lasts

$\rightarrow - 3 \times - 8 = 24$

Now put them all together

$\rightarrow 25 {y}^{2} - 40 y - 15 y + 24$

color(green)(rArr25y^2-55y+24

Hope that helps!!! ☺•☻

Nov 4, 2017

Given: $\textcolor{b l u e}{\left(5 y - 3\right)} \textcolor{g r e e n}{\left(5 y - 8\right)}$

Multiply everything in the right brackets by everything in the left.
Note that the minus in $\textcolor{b l u e}{- 3}$ follows the three.

$\textcolor{g r e e n}{\textcolor{b l u e}{5 y} \left(5 y - 8\right) \textcolor{b l u e}{\textcolor{w h i t e}{\text{ddd")-color(white)("ddd}} 3} \left(5 y - 8\right)}$

$25 {y}^{2} - 40 y \textcolor{w h i t e}{\text{ddddd}} - 15 y + 24$

$25 {y}^{2} - 55 y + 24$

Nov 4, 2017

color(magenta)(25y^2-55y+24

#### Explanation:

$\left(5 y - 3\right) \left(5 y - 8\right)$

$\textcolor{w h i t e}{a a a a a a a a a a a a a a}$$5 y - 3$
$\textcolor{w h i t e}{a a a a a a a a a a a}$$\times \underline{5 y - 8}$
$\textcolor{w h i t e}{a a a a a a a a a a a a a}$$25 {y}^{2} - 15 y$
$\textcolor{w h i t e}{a a a a a a a a a a a a a a a a a}$$- 40 y + 24$
$\textcolor{w h i t e}{a a a a a a a a a a a a a}$$\overline{25 {y}^{2} - 55 y + 24}$

$\textcolor{w h i t e}{a a a a a a a a a a a a a}$color(magenta)(25y^2-55y+24