Question

How do you solve `\frac { 16} { x + 4} = \frac { 4} { 7}`?

Answer 1

`x=24`

Explanation:

`"one way is to use the method of "color(blue)"cross-multiplying"`

`•color(white)(x)a/b=c/drArrad=bc`

`rArr16/(x+4)=4/7larrcolor(blue)"cross-multiply"`

`rArr4(x+4)=16xx7`

`rArr4x+16=112`

`"subtract 16 from both sides"`

`4xcancel(+16)cancel(-16)=112-16`

`rArr4x=96`

`"divide both sides by "4`

`(cancel(4) x)/cancel(4)=96/4`

`rArrx=24`

`color(blue)"As a check"`

Substitute this value into the equation and if both sides are equal then it is the solution.

`16/(24+4)=16/28=cancel(16)^4/cancel(28)^7=4/7`

`rArrx=24" is the solution"`