Question 1182
 Use |ax +b|<= c is equivalent to -c <= ax+b <= c 
 We see that |3x + 4| <= 7 is equivalent to
 -7 <= 3x+4 <= 7
 Subtract 4 on each term, we have
 -11 <= 3x <= 3,
 Divide each term by 3, we get
 -11/3 <= x <= 1.

 Hence, the solutin set is [-11/3, 1].