Answer:
m = 2
Step-by-step explanation:
Given:
x = 4
y = 6m - 2
a = 8
b = 5
Required:
Value of m
SOLUTION:
x and y are segments of a chord divided when it intersects another chord that also has segments a and b.
According to the Intersecting chords theorem, 
Thus:

Solve for m





The value of m = 2
We are asked to determine the value of a such that the function f(x) = ax^2 + 5 is fit for the point given (-1,2). In this case, we substitute 2 to y and -1 to x. The result is then 2 = a*(-1)^2 + 5 ; 2 = a + 5; a is then equal to -3
Since the question is asking how fast he is driving, we need to find his speed in miles per hour. To do this, you need to divide the amount of miles he drove by the amount of hours it took. When you do 412.5/7.5, you get the answer of 55 miles per hour.