Write the equation of a parabola with vertex (2,-1) and directrix y=-3

Step-by-step explanation:

a parabola is the graph of a quadratic equation, so the general equation is

If the directrix is negative, it means the graph opens down, so a is -

and c is -3

this gives us

all we need now is what is b

b is the y intercept for

to find the y intercept, we plug in 0 for x

so the y intercept is -3

so the equation is

see explanation

step-by-step explanation:

since the sequence is geometric there is a common ratio r between consecutive terms, that is

r = 4 ÷ - 2 = - 2

r = - 8 ÷ 4 = - 2

r = 16 ÷ 8 = - 2

the next term - 13 must be incorrect as it should be - 32 for the sequence to be geometric.

the first 4 terms are therefore geometric with common ratio r = - 2

i believe the answer is d.

hope it you! : d