The sequence
1, 3, 7, 13, 21, ...
has first-order differences
2, 4, 6, 8, ...
Let 
denote the original sequence, and 
the sequence of first-order differences. It's quite clear that
for 
. By definition of first-order differences, we have
for , or
By substitution, we have
and so on, down to
You should know that
and we're given 
, so
or
Alternatively, since we already know the sequence is supposed to be quadratic, we can look for coefficients 
such that
We have
and we can solve this system for the 3 unknowns to find 
.
Answer:
Negative 4 StartRoot 3 EndRoot and 4 StartRoot 3 EndRoot
Step-by-step explanation:
The answer is C the whole shape it a rectangle the two triangles in it are going to be congruent.
Answer: y-intercept: (0, -0.7) and x-intercept: (-1.2, 0)
Recall: The coordinate of a point is always written as (x,y).
Look to the x- and y-axis and see where there's a point that's exactly on it; that'll be your x- and y-intercept.
The point (0, -0.7) is on the y-axis, so that's your y-intercept. The point (-1.2, 0) is on the x-axis, so that's your x-intercept.
