How do I solve the polynomial inequality #-12<-2(x+1)<=18#?

1 Answer
Sep 10, 2014

#-12<-2(x+1)<=18#

Step 1: Divide all three "parts" by -2 and switch the direction of the inequality symbols.

#6>x+1>=-9#

Step 2: subtract 1 from all three "parts".

#5 > x >= -10#

For your solution, you may need to draw a number line. Be sure to use an open circle at 5 and a closed circle at -10.

my number line

My students are also required to use interval notation: #[-10,5)#