Slope is m= y2- y1 / x2- x1.
Billy flipped both where the numbers go, and in which order they should be in.
It should be -5-5 / -2-2 giving you zero (0).
I must assume that you meant the following:
10(Q-3R)
P = ----------------
R
Multiplying both sides by R, we get PR = 10R(Q-3R), or PR = 10RQ - 30R^2.
Rearranging these terms so that powers of R are in descending order:
30R^2 - 10RQ + PR = 0
Factoring out R, we get
R(30R - 10Q + P) = 0. This has two solutions:
R = 0, and 10Q - P
30R = 10Q - P, so that R = --------------
30
12/3 = 4 minutes
4 minutes per kilometre
4x7=28
28 minutes
The mean is when you add up all the numbers and divide by the amount of numbers there are.
143+312+41+28+308+619+321+352+465=2589
2589/9=287.666666667
round to the whole number you get
288