X²-9x=36
minus 36 both sides
x²-9x-36=0
what 2 numbers multiply to -36 and add to -9
-12 and 3
(x-12)(x+3)=0
set to zero
x-12=0
x=12
x+3=0
x=-3
the number is either -3 or 12
Solve for k using graphed value:
96 = k6
k = 16
y = 16x
Another given value of x is 12. 12•16 = 192, so that checks out ok.
We can see that for every 1 hour he increases 10 miles in his distance, so we can say it's constant, he started at 0 and increased 10 miles per hour.
Alternative C.
Percentage decrease = d
h1 = 2950
h2 = 2550
d/100 = (h2-h1)/h1
d/100 = (2950-2550)/2950
d=13.56
