Let

be the statement that

Check to see that

holds for

:

Now suppose that

is true, and use that assumption to show that

must also be true. When

, you have




and so

is also true, thus proving the statement is true for all

.
The vertex of the quadratic function is: A) (0,2)
80% of quizzes + 20% of final = final grade
80% * 73 + 20% * x = 70
0.8 * 73 + 0.2x = 70
58.4 + 0.2x = 70
0.2x = 11.6
x = 58
I’m not sure what the negative fours are at the end of your problem are for, but the slope of the line passing through those points is 4.
The line itself is y = 4x - 11