Question

How do you solve `45a = 9`?

Answer 1

`a=1/5`

Explanation:

`45a=9` Isolate `a` (divide each side by `45`)
`(45a/45)=(9/45)` (`45/45=1`)
`a=9/45` Simplify 9/45 by dividing by `9`
`a=(9/9)/(45/9)`
`a=1/5`

Answer 2

`a = 0.2`

Explanation:

To solve this type of equation, you need to isolate the variable by itself on one side of the equation. The variable in this problem is `a`.

`45a` means the same thing as `45 xx a`, so it means multiplication:

Since we see multiplication, we know that we have to use the opposite function, which would be division to isolate `a`.

OPPOSITES:

`color(red)"addition"` `harr` `color(blue)"subtraction"`
`color(red)"multiplication"` `harr` `color(blue)"division"`

So we will divide both sides by `45` to isolate `a`. Since the one side is already being multiplied by `45`, we can cancel the `45`'s:

`(cancel45a)/cancel45 = 9/45`

`a = 9/45`

Now just divide `9` by `45`

`a = 0.2`