Question

How do you solve `2( 9- 2y ) = 21`?

Answer 1

`y=(-3)/4`

Explanation:

`2(9-2y)=21`

Let's start by using the distributive property

`(2)(9)+(2)(-2y)=21`

`18 - 4y = 21`

Then subtract `color(red)(18)` from both sides

`cancel18 - 4y - cancelcolor(red)(18) = 21 - color(red)(18)`

`-4y = 3`

Then finally, divide both sides by `color(green)(-4)`

`(cancel(-4)y)/cancelcolor(green)(-4) = 3/color(green)(-4)`

`y=(-3)/4`

Answer 2

Graphical Interpritation...

Explanation:

Graphical Approach

Since `2(9-2y) = 21`

Both sides are equal to the same thing:

Let `x = 2(9-2y) and x = 21`

Now sketching each of the functions...

![www.desmos.com]()

Now the solution to the question is were the interesection is, hence lieing on both lines, and satifying each equation

So in this case, solving for `y`;

`color(blue)(y = -0.75 = -3/4`