How do you solve #13+ - 4r = - 15#?

1 Answer
Dec 28, 2016

#r = 7#

Explanation:

Step 1) Subtract #color(red)(13)# from each side of the equation to isolate the #r# term and keep the equation balanced:

#13 + -4r - color(red)(13) = -15 - color(red)(13)#

#13 - color(red)(13) + -4r = -28#

#0 + -4r = -28#

#-4r = -28#

Step 2) We now divide each side of the equation by #color(red)(-4)# to solve for #r# while keeping the equation balanced:

#(-4r)/color(red)(-4) = (-28)/color(red)(-4)#

#(-4r)/color(red)(-4) = 7#

#(color(red)(cancel(color(black)(-4)))r)/cancel(color(red)(-4)) = 7#

#r = 7#