M is the slope.
B is the y-intercept
The constant of proportionality is the ratio between two directly proportional quantities.
Cant really see it the picture
You have to complete the square to get it into vertex form. Do this by setting the function equal to zero and at the same time moving the constant over to the other side of the equals sign so you have this:

. Now we can complete the square on the polynomial by taking half the linear term, squaring it, and adding it to both sides. Our linear term is 4. Half of 4 is 2, and 2 squared is 4, so we add 4 to both sides:

and simplify to get

. In this process we have created a perfect square binomial on the left, which happens to be

. Now move the -6 back over by addition to get

. The vertex is found at (-2, 6), the third choice down.
If Tony bought 20 out of 80 tickets, then it would be 25% because 20 is 1/4 of 80.
Hope I helped!
64° i think because. its an iscoceles triangle so the bottom two angles are the same so you do 58+58=116 and because all angles in a triangle add to 180° you do 180-116=64°