Just find the slope between the points
basically find (f(10)-f(7))/(10-7)
f(7)=7^2-3(7)-4=49-21-4=24
f(10)=10^2-3(10)-4=100-30-4=66
slope=(66-24)/(10-7)=42/3=14
average rate of change is 14
A+s=496
s=496-a
and we are also told that:
s=3a
Since s=s we can say:
3a=496-a add a to both sides
4a=496 divide both sides by 4
a=124
So 124 adult tickets were sold.
Answer:
Inequality 7n - 22 >= 64
Solution 7n > = 64 + 22
7n >= 86
n => 12. 28 rounded down to 12
Grace must wash at last 12 cars