68 minus 19 is 49
So the answer is there are 49 more children in the school then on the playground.
Y=(-1/6)x+5
m=(y2-y1)/(x2-x1)
m=(3-6)/(12-(-6))
m=(-3)/(18)
m=-1/6
y=mx+b
y=(-1/6)x+b
6=(-1/6)(-6)+b
6=1+b
b=5
y=(-1/6)x+5
X = -3, y = 2 rise over run