Hello from MrBillDoesMath!
Answer:
#11. Your choice, 3x + 1 <= 4, is correct
#13 Your choice, 8p +5 > 21. is correct
Discussion:
#11, Let's explore: 3x + 1 <= 4
3x + 1 <= 4 =>
3x + 1 -1 <= 4 - 1 => (subtract 1 from both sides)
3x <= 3 =>
x <=1
which matches the red line segment shown. In the diagram, the point x = 1 is included (a solid dot) as in our solution x <=1.
#13. The second radio button, the one you selected, is correct. Let's explore:
8p + 5 > 21 =>
8p + 5 -5 > 21 - 5 (subtract 5 from both sides)
8p > 16 (as 21-5 = 16)
p > 2 (divide both sides by 8)
Note that this solution, like the graph ("open circle" at 2) does NOT include the point p = 2
Regards,
MrB
P.S. I'll be on vacation from Friday, Dec 22 to Jan 2, 2019. Have a Great New Year!