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

1 Answer
Sep 30, 2017

Answer:

#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"#