15/50 = 3/30 = 1/10
1/10 = 10%
That is about as simple as I could put it.
Answer: x<16
Step-by-step explanation: Mason subtracted 5 from 11 and got 6, when he really should have added 5 to 11 to get x<16.
I hope this makes sense, if not please feel free to let me know and I'll explain it.
The intercepts and the graph on your worksheet are not correct. Please see below for details:
has solutions at x=-1 and x=3 (use the quadratic formula to solve). That means these are the x-intercepts, namely points:
(-1,0) and (3,0).
The y-intercept comes from setting x=0 and calculating the y value:

so the y-intercept is (0,-3).
Now to the graph: Based on the form of the function we can see this is a quadratic function and its graph will be a parabola. You can reformat the expression in the following form

and that will indicate that the apex of the parabola (open up) will be at the point (1,-4).
Knowing the apex, the x intercepts, and the y intercept, we can graph it now.
Graph is in the image attached.
–3x + 5.9 ≥ –15.4
subtract 5.9 from each side
-3x >= -21.3
divide by -3 which causes the inequality to flip
x <= 7.1
Answer: -10,-5,0,5