10. The measure of an obtuse angle is represented by (9x + 27)º. Which is not a possible value for x?

For the first one, D is correct.....an obtuse angle is > 90....but 9(6.8)+ 27 = 88.2

For the second one, we have

5x + 7(-4) ≥ 22    simplify

5x - 28 ≥ 22        add 28 to each side

5x ≥ 50               divide by 5 on both sides

x ≥ 10

So C is correct

Obtuse angle (obtuse angle), is an angle that greater than the right angle (90 °) is smaller than a straight angle (180 °) . Obtuse angle is formed by two rays.(180>x>90)

 so 180>9x+27>90 

     20>x+3>10 (both side divede by 9)

     17>x>7

 so it could have three  anwser B 12.3 , C 16.9  A.7.1

 but assume you typed the question wrong it,s an acute angle  refers to an angle that  greater than 0 ° but less than 90 ° 

 so 90>27+9x>0

     63>9x>-27

    7>x>-3

 then , there is only one anwser  D 6.8

is it right?