Recall that
There are three cases to consider:
(1) When
, we have
and
, so
(2) When
and
, we get
and
, so
(3) When
, we have
and
, so
So
Answer:
480
Step-by-step explanation:
Sn = n÷2 × (2a + (n-1)d)
n = 20 a = -14 d = 4
S20 = 10 × (-28 + 19 × 4) = 480
Answer:
I have found unreliable people would leave message and fail to answer properly and not always report but then found their answer was deleted later- but sometimes its straight away as repeat offenders often have all of their answers deleted at once
Answer:
If you call the smaller integer "x" and the greater integer "y", then:
x+y=3x-11 The sum of the two is 11 less than 3 times the smaller
y=x+1 Because they are consecutive, the greater must be 1 more than the smaller
Then you can solve for x:
x+(x+1)=3x-11 Substitute x+1 for y
2x+1=3x-11 Combine like terms
2x+12=3x Add 11 to both sides
12=x Subtract 2x from both sides
The smaller integer is 12, thus the greater integer is 1 more or 13.
Check:
12+13=3(12)-11
25=36-11
25=25 Yes, so the integers are 12 and 13
Step-by-step explanation:
thats pretty much it
