The sequence is an arithmetic sequence with
a₁ = -4
d = a₂ - a₁
d = -1 - (-4)
d = -1 + 4
d = 3
an = x
Sn = 437
General formula in arithmetic sequence
Formula to find nth term
an = a₁ + d(n - 1)
Formula to find sum of sequence (sn)
Sn = n/2 (a₁ + an)
We have to make an equation system based on the problem
plug the numbers into the formula
First equation
an = a₁ + d(n - 1)
x = -4 + 3(n - 1)
x = -4 + 3n - 3
x = 3n - 7
Second equation
Sn = n/2 (a₁ + an)
n/2 (a₁ + an) = 437
n/2 (-4 + x) = 437
n(x - 4) = 874
xn - 4n = 874
Solve the equation system by subtitution method
Subtitute x with 3n - 7 in the second equation
xn - 4n = 874
(3n - 7)n - 4n = 874
3n² - 7n - 4n = 874
3n² - 11n - 874 = 0
(3n + 46)(n - 19) = 0
n = -46/3 or n = 19
Because the number of terms shouldn't be negative, -46/3 isn't required, so the value of n is 19.
Solve for x, back to the first equatin
x = 3n - 7
x = 3(19) - 7
x = 57 - 7
x = 50
The solution is 50
Answer:
so you got ehffffffffff
Step-by-step explanation:
Answer:
+3x + 7 to make the sum x3
Step-by-step explanation:
to find the sum of 3 and to solve it to get the value of x
Ok. First, Kym went to bed at 8:30. There are only 60 minutes in an hour. 10 minutes to make her bed. 8:30 - 10 = 8:20. She had a 25 minute bath "jeez that's long" 8:20 - 25 = 7:55. Kym spent 15 minutes folding clothes: 7:55 - 15 = 7:40. She began to start folding clothes at 7:40.
Answer:<span> B. 7:40 p.m.
Or you could do it the easy way.
15 + 25 + 10 = 50
50 - 8:30 = 7:40
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