Which of the following is an arithmetic sequence? –20, –25, –30, –35, –45, ... –15.6, –12.9, –10.2, –7.5, –4.8, ... 3.1, 6.2, 12
Leona [35]
Answer:
A
Step-by-step explanation:
Because you can't multiply -20 times anything to get -25 you just add -5
Answer:
1, 5, 2, 4, 3, 7, 6
Step-by-step explanation:
After dividing by the leading coefficient, each equation can be put into the form ...
x² + y² + ax +by +c = 0
Subtracting c and separately completing the square for x-terms and y-terms, we get ...
x² + ax + (a/2)² + y² + by + (b/2)² = -c + (a/2)² + (b/2)²
(x +a/2)² + (y +b/2)² = r² = (a/2)² + (b/2)² -c . . . . . rewrite in standard form
Ordering by the square of the radius length will match the ordering by radius length, so we just need to compute (a/2)² +(b/2)² -c for each given equation. I find it convenient to let a calculator or spreadsheet do this calculation (see attached).
In the order the equations are given, the square of the radius is ...
3, 18, 45, 23, 5, 117, 46
So the order of the equations from smallest radius to largest is ...
1, 5, 2, 4, 3, 7, 6
For the axis of symmetry it will be -b/2a but in this case the axis of symmetry is going to be y=4. the x intercept will be the roots (2,0) and (6,0) and for the y intercept it will be (0,3) since the parabola crosses the y axis at (0,3)
I think it lacks logical......................
6,600,000,000 in scientific notation is 6.6 × 10^9