How do you solve #4 < 13 +r#?

1 Answer
Jun 2, 2015

Subtract #13# from both sides to get:

#-9 < r#

That is #r > -9#

In general, you can perform any of the following operations on an inequality and preserve its truth:

(1) Add or subtract a value on both sides.
(2) Multiply or divide by a positive value on both sides.
(3) Multiply or divide by a negative value on both sides and reverse the inequality (#<# becomes #>#, #>=# becomes #<=#, etc).