12x-39greater than 9 and -4x+3<-6

Accepted Solution

Answer:Step-by-step explanation:When you have an inequality like this, you can treat it like an equation except for one part.  If you ever divide or multiply it by a negative number or variable you have to flip the inequality.  if it is equal to as well you keep that though.  for instance -5x ≤ 10x ≥ -2Anyway, in your case you have two inequalities, so you have to solve both and see what makes both true.We'll start with 12x - 39 ≤ 912x - 39 ≤ 9 First add 39 to both sides12x ≤ 48 Now divide both sides by 12, positive so no flippingx ≤ 4Next is:-4x + 3 < -6 First subtract 3 from both sides-4x < -9 Now divide both sides by -4, which means the sign flipsx > 9/4Now, without even looking at the answers, what number or numbers are  less than or equal to 4 and greater than 9/4?  Well we pretty much described it there.  All numbers starting from, though not including 9/4, which is 2.25, all the way up to, and including 4.  B shows exactly that.