How do you write an inequality and solve given "a number decreased by 8 is less than 21"?

1 Answer
Jan 25, 2017

Answer:

See the entire solution process below:

Explanation:

First, write the inequality.

Let's call the number we will be solving for #n#.

Therefore "a number decreased by 8" can be written as:

#n - 8#

"is less than 21" can be written as:

#< 21#

Putting this altogether gives:

#n - 8 < 21#

To solve for #n# add #color(red)(8)# to each side of the inequality which will solve for #n# while keeping the inequality balanced:

#n - 8 + color(red)(8) < 21 + color(red)(8)#

#n - 0 < 29#

#n < 29#