A student solved the following problem.
1 answer:
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Answer:
-125
Step-by-step explanation:
Each term is 7 less than the previous term.
1st term: 15
2nd term: 15 - 7
3rd term: 15 - 7 - 7 = 15 - 2(7)
4th term = 15 - 7 - 7 - 7 = 15 - 3(7)
Notice that each term is 15 minus a multiple of 7. The multiple is obtained by multiplying 7 by 1 less than the term number.
The formula is:
For the 21st term, multiply 7 by 20, and subtract from 15.
7 × 20 = 140
15 - 140 = -125
Using the formula:
Answer: -125
The equation of c is an illustration of subject of formula
The equation of c in terms of r and t is c = r - 15/t
<h3>How to determine the equation?</h3>The equation is given as:
t = 15/(r - c)
Cross multiply
t(r - c) = 15
Divide both sides by t
r - c = 15/t
Subtract r from both sides
-c = -r + 15/t
Multiply both sides by -1
c = r - 15/t
Take LCM
Hence, the equation of c in terms of r and t is
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