Answer:
ayyy im on de same ?
Step-by-step explanation:
ayyyyyy!
The vertex of the parabola is between the shortest line connecting its focus and directrix, so between (0, -4) and y = 4 is the point (0, 0), which is the vertex of the parabola. Also, this parabola faces downward.
The general formula for a parabola that faces downward is y = -4cx^2, where c is the distance from the vertex to either to focus or the parabola. Since c = 4, the equation is y = -16x^2, which is choice A.
42 received an A
so 40-42 = 38 did not
the fraction would be 38/80, divide both numbers by 2
38/80 reduces to 19/40 did not receive an A
There are two ways to do this but the way I prefer is to make one of the equations in terms of one variable and then 'plug this in' to the second equation. I will demonstrate
Look at equation 1,

this can quite easily be manipulated to show

.
Then because there is a y in the second equation (and both equations are simultaneous) we can 'plug in' our new equation where y is in the second one

which can then be solved for x since there is only one variable

and then with our x solution we can work out our y solution by using the equation we manipulated

.
So the solution to these equations is x=-2 when y=6
After
using a calculator to find sin 21 degrees and rounding it to four decimal places,
I got 0.3584. The correct answer between all the
choices given is the first choice. I am hoping that this answer has satisfied
your query and it will be able to help you in your endeavor, and if you would
like, feel free to ask another question.