Answer:
Step-by-step explanation:
Given the explicit function as
f(n) = 15n+4
The first term of the sequence is at when n= 1
f(1) = 15(1)+4
f(1) = 19
a = 19
Common difference d = f(2)-f(1)
f(2) = 15(2)+4
f(2) = 34
d = 34-19
d = 15
Sum of nth term of an AP = n/2{2a+(n-1)d}
S20 = 20/2{2(19)+(20-1)15)
S20 = 10(38+19(15))
S20 = 10(38+285)
S20 = 10(323)
S20 = 3230.
Sum of the 20th term is 3230
For the explicit function
f(n) = 4n+15
f(1) = 4(1)+15
f(1) = 19
a = 19
Common difference d = f(2)-f(1)
f(2) = 4(2)+15
f(2) = 23
d = 23-19
d = 4
Sum of nth term of an AP = n/2{2a+(n-1)d}
S20 = 20/2{2(19)+(20-1)4)
S20 = 10(38+19(4))
S20 = 10(38+76)
S20 = 10(114)
S20 = 1140
Sum of the 20th terms is 1140
Answer:
9x^2 -49
Step-by-step explanation:
We recognize that this is of the form
(a+b)(a-b) = a^2 - b^2
3x = a and 7 =b
(3x)^2 - 7^2
9x^2 -49
Answer:
A and C
Step-by-step explanation:
I just answered the question.
Answer:
d = 0.7*t
Step-by-step explanation:
Given data,
Time Distance
10 7
15 10.5
20 14
From analysis,
1) d1/t1 = 7/10 = 0.7
2) d2/t2 = 15/20 = 0.7
3) d3/t3 = 14/20 = 0.7
It can be analysed from the figure that, at every point d/t = 0.7
Therefore, the relationship between t and d is
d = 0.7*t
or
t = d/0.7
