Answer:
1 seconds after being thrown, the stone reaches its max height
Step-by-step explanation:
The parabolic (quadratic) equation is:

Lets expand this in the form
, so we have:

We can say the values of a,b, and c, now to be:
a = -5
b = 10
c = 40
The number of seconds at which the max would occur is given by the point, x, at:

We know a and b, let's find the seconds, x,

Hence,
1 seconds after being thrown, the stone reach its max height
The answer would be D if it was 250-6-3n. it wouldnt be A or C because 9 isnt anywhere in the problem and it wouldnt be B because she used 6 peices of paper she didnt just give it to her students
Hello!
To solve this question, we must first add the exponent into the number 7 before multiplying it by the number 6.
7 to the second power simply means 7x7.
7x7= 49
Now that the exponent is in the equation, we can multiply 49 by 6 to find your final answer.
6 x 49 = 294
I hope this helps answer your question! Have a great day!
-MMMski