Answer:
10:12:15
Step-by-step explanation:
a/b=5/6
b/c=4/5
thus
c/b=5/4
LCM of 4 and 6=12
5/6=10/12
5/4=15/12
b is the 12 in both
thus ratio between a:b:c is 10:12:15
i can reply in comments if more explanation is needed
Answer:
y = 15
Step-by-step explanation:
Given: y varies directly with x, x=4 when y=20
To find: y when x = 3
Solution:
As y varies directly as x, it means that as x increases, y also increases by the same factor.
As y varies directly with x,
Here, k is a constant
As x = 4 when y = 20,
Put x = 3
Answer:
Step-by-step explanation:
The first differences of the sequence are ...
- 5-2 = 3
- 10-5 = 5
- 17-10 = 7
- 26-17 = 9
- 37-26 = 11
Second differences are ...
- 5 -3 = 2
- 7 -5 = 2
- 9 -7 = 2
- 11 -9 = 2
The second differences are constant, so the sequence can be described by a second-degree polynomial.
We can write and solve three equations for the coefficients of the polynomial. Let's define the polynomial for the sequence as ...
f(n) = an^2 + bn + c
Then the first three terms of the sequence are ...
- f(1) = 2 = a·1^2 + b·1 + c
- f(2) = 5 = a·2^2 +b·2 + c
- f(3) = 10 = a·3^2 +b·3 +c
Subtracting the first equation from the other two gives ...
3a +b = 3
8a +2b = 8
Subtracting the first of these from half the second gives ...
(4a +b) -(3a +b) = (4) -(3)
a = 1 . . . . . simplify
Substituting into the first of the 2-term equations, we get ...
3·1 +b = 3
b = 0
And substituting the values for a and b into the equation for f(1), we have ...
1·1 + 0 + c = 2
c = 1
So, the formula for the sequence is ...
f(n) = n^2 + 1
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The 20th term is f(20):
f(20) = 20^2 +1 = 401
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<em>Comment on the solution</em>
It looks like this matches the solution of the "worked example" on your problem page.
<span>(5h^3 − 8h) + (−2h^3 − h^2 − 2h)
= 5h^3 - 8h - 2h^3 - h^2 - 2h
= 3h^3 - h^2 - 10h</span>
