Answer:
The common difference (or common ratio) = 0.75
Step-by-step explanation:
i) let the first term be = 80
ii) let the second term be =
. r = 80 × r = 60 ∴ r =
= 0.75
iii) let the third term be =
. r = 60 × r = 45 ∴ r =
= 0.75
iv) let the fourth term be =
. r = 45 × r = 33.75 ∴ r =
= 0.75
Therefore we can see that the series of numbers are part of a geometric progression and the first term is 80 and the common ratio = 0.75.
So before I put the equation into standard form, I'm first going to be putting it into vertex form. Since the vertex appears to be (-1,7), plug that into the vertex form formula:
Next, we need to solve for a. Looking at this graph, another point that is in this line is the y-intercept (0,5). Plug (0,5) into the x and y placeholders and solve for a as such:
Now we know that <u>our vertex form equation is y = -2(x + 1)^2 + 7.</u>
However, we need to convert this into standard form still, and we can do it as such:
Firstly, solve the exponent:
Next, foil -2(x^2+2x+1):
Next, combine like terms and <u>your final answer will be: </u>