How do you solve #\frac { r } { 21} - 3= 2#?

1 Answer
Apr 7, 2017

See the entire solution process below:

Explanation:

First, add #color(red)(3)# to each side of the equation to isolate the #r# term while keeping the equation balanced:

#r/21 - 3 +color(red)(3) = 2 + color(red)(3)#

#r/21 - 0 = 5#

#r/21 = 5#

Now, multiply each side of the equation by #color(red)(21)# to solve for #r# while keeping the equation balanced:

#color(red)(21) xx r/21 = color(red)(21) xx 5#

#cancel(color(red)(21)) xx r/color(red)(cancel(color(black)(21))) = 105#

#r = 105#