Question

How do you solve `7.1= 3.8+ n`?

Answer 1

`n=3.3`

Explanation:

Given: `7.1=3.8+n`

Don't like decimals so lets get rid of them. Multiply everything on both sides by 10

`71=38+10 n`

As per convention put the unknown on the left. So turn everything round the other way

`10n+38=71 larr" Means exactly the same thing"`

Subtract `color(red)(38)` from both sides

`color(green)(10n+38=71 color(white)("ddd")->color(white)("ddd")10n+38color(red)(-38)color(white)("d")=color(white)("d")71color(red)(-38) )`

`color(green)(color(white)("ddddddddddddd.d")->color(white)("ddd")10n + color(white)("dd")0color(white)("ddd.")=color(white)("ddd")33)`

Divide both sides by `color(red)(10)`

`color(green)(10n=33color(white)("ddddddd")->color(white)("ddd")10/color(red)(10)ncolor(white)("d")=color(white)("d")33/color(red)(10) )`

But `10/10=1 and 1xxn = n` giving:

`color(green)(n=3.3)`