Find an equation for the nth term of the arithmetic sequence. -1, 2, 5, 8, ...
2 answers:
Answer:
The expression for the n-th term is
Step-by-step explanation:
We know that the n-th term of an arithmetic progression is given by . So we need to find the coefficients
and
. In order to do this, we substitute the values
and
in the expression for
:
Now, notice that we have two linear equations with two unknowns, which it is not difficult to solve. Thus, the solution is and
.
Hence, the expression for the n-th term is
We can check that the expression is correct substituting the values which gives
and
which gives
, as it is given in the statement of the problem.
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Answer:
It takes 1 seconds for push-ups and 3 seconds for sit-ups for Mei to do exercise.
Step-by-step explanation:
Given:
Let the time taken for push-ups be 'x'.
Let the time taken for sit-ups be 'y'.
Now Given:
17 push-ups and 6 sit-ups, it takes a total of 35 seconds.
So we can say that;
Also Given:
41 seconds to do 20 push-ups and 7 sit-ups.
so we can say that;
Now Multiplying equation 1 by 7 we get;
Now Multiplying equation 2 by 6 we get;
Now Subtracting equation 3 from equation 4 we get;
Now substituting the value of x in equation 1 we get;
Hence It takes 1 seconds for push-ups and 3 seconds for sit-ups for Mei to do exercise.