Question

How do you solve the proportion `(x+1)/(x +3) = 15/21`?

Answer 1

`x=4`

Solution

`(x+1)/(x+3)=15/21`

`(x+1)(21)=15(x+3)`

`21x+21=15x+45`

`21x-15x=45-21`

`6x=24`

`x=24/6`

`x=4`