Q. Find the 14 th term of the arithmetic sequence −2x−3,−6x−9,−10x−15,…Answer:
Verify Common Difference: Verify that the common difference remains consistent by subtracting the second term from the third term.−10x−15−(−6x−9)=−10x−15+6x+9=−4x−6This confirms that the common difference is indeed −4x−6.
Use Arithmetic Sequence Formula: Use the formula for the nth term of an arithmetic sequence: an=a1+(n−1)d, where an is the nth term, a1 is the first term, and d is the common difference.Here, a1=−2x−3, d=−4x−6, and n=14.
Substitute Values: Substitute the values into the formula to find the 14th term.a14=−2x−3+(14−1)(−4x−6)a14=−2x−3+13(−4x−6)
Simplify Expression: Simplify the expression by distributing 13 into (−4x−6). a14=−2x−3+(−52x−78)a14=−2x−3−52x−78
Combine Like Terms: Combine like terms to get the final expression for the 14th term.a14=−54x−81
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