How do you solve the compound inequalities #60 < 20u < 120#?

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Answer 1 · 2018-07-15T12:50:06

#u in(3,6)#

#"divide all intervals by 20"#

#3< u < 6" is the solution"#

#u in(3,6)larrcolor(blue)"in interval notation"#

Answer 2 · 2018-07-15T15:52:11

#3 < u < 6#

Interval notation: #(3,6)#

Remember, the end goal is to isolate #u#. To go about doing this, we can divide all intervals by #20#. We get

#3 < u < 6#

This means the solutions of this inequality are values of #u# between #3# and #6#, not including those.

We can alternatively write this in interval notation as

#(3,6)#

Notice that we used parenthesis as opposed to brackets when we don't include the end values.

Hope this helps!