Answer:

Step-by-step explanation:
In order to write the series using the summation notation, first we need to find the nth term of the sequence formed. The sequence generated by the series is an arithmetic sequence as shown;
4, 8, 12, 16, 20...80
The nth term of an arithmetic sequence is expressed as Tn = a +(n-1)d
a is the first term = 4
d is the common difference = 21-8 = 8-4 = 4
n is the number of terms
On substituting, Tn = 4+(n-1)4
Tn = 4+4n-4
Tn = 4n
The nth term of the series is 4n.
Since the last term is 80, L = 4n
80 = 4n
n = 80/4
n = 20
This shows that the total number of terms in the sequence is 20
According to the series given 4 + 8 + 12 + 16 + 20+ . . . + 80
, we are to take the sum of the first 20terms of the sequence. Using summation notation;
4 + 8 + 12 + 16 + 20+ . . . + 80 = 
Answer:
X would have to equal 6. To work it out, you subtract 4 from each side to cancel out the 4. -x = -6. You have to make -x just x so you × each side by -1. You get x = 6.
The answer should be $8 if you are trying to find the unit rate. All you have to do is divide 32 by 4 and you get 8. Hope that helped.
Answer:
after 10 months
Step-by-step explanation:
Let x be the number of months and y be the amount they still owe.
Sin Ian borrows $1000 from his parents, then the y-intercept b= 1000 since he owes $1000 when x = 0. He pays them back $60 each month The slope is then m = -60 . Substituting in b = 1000 and m = -60 into the slope-intercept form of a line then gives y= mx + b=-60x +1000.
Sin Ken borrows $600 from his parents, then the y-intercept b = 600 since he owes $600 When x= 0. He pays them back $20 per month so the amount he owes decreases $20 each month. The slope is then m = -20 . Substituting in
b= 600 and m = -20 into the slope-intercept form then gives y = mx +b = -20x + 600.
They will owe the same amount when they have the same y-coordinate. Therefore -60x+ 1000= y= -20x+600. Solve this equation for x:
-60x+ 1000 = -20x+ 600
1000 = 40x+ 600
400 = 40x
10=x
They will then owe the same amount after 10 months.
Answer:
8x+8?
Step-by-step explanation:
2x+6x=8x
5+3=8