Step-by-step explanation:
Sn=n/2(2a+(n-1)d)
910=n/2{2a+(n-1)d}
1820=n{2a+(n-1)d}
1820=20{2a+(20-1)d}
1820=20{2a+19d}
91=2a+19d
An=a+(n-1)d
95=a+(20-1)d
95=a+19d
91=2a+19d
---------------
4=-a
a=-4
91=2a+19d
91=2(-4)+19d
91=-8+19d
91+8=19d
99=19d
d=99/19
A=-4
The answer i think is it c
If you're asking the difference between 14 ft and 21 ft your answer is 7 ft, just subtract 14 from 21
The slope of this line is -2.
rise/run
rise = 4
run = -2
4
------- = -2
-2
Using the points (1,0) & (0,2)
2 - 0 2
----------- = ----- = -2
0 - 1 -1