Q. Find the 7 th term of the arithmetic sequence 5x−4,−2x−9,−9x−14,…Answer:
Find Common Difference: To find the 7th term of an arithmetic sequence, we need to determine the common difference between consecutive terms and then use the formula for the nth term of an arithmetic sequence, which is an=a1+(n−1)d, where an is the nth term, a1 is the first term, and d is the common difference.
Calculate Common Difference: First, let's find the common difference d by subtracting the first term from the second term.d=(−2x−9)−(5x−4)d=−2x−9−5x+4d=−7x−5
Use Formula for 7th Term: Now, let's verify the common difference by subtracting the second term from the third term.d=(−9x−14)−(−2x−9)d=−9x−14+2x+9d=−7x−5This confirms that the common difference is indeed −7x−5.
Simplify 7th Term Expression: Using the formula for the nth term, we can now find the 7th term a7.a7=a1+(7−1)(−7x−5)a7=(5x−4)+6(−7x−5)
Simplify 7th Term Expression: Using the formula for the nth term, we can now find the 7th term a7.a7=a1+(7−1)(−7x−5)a7=(5x−4)+6(−7x−5)Let's simplify the expression for the 7th term.a7=5x−4+6(−7x)+6(−5)a7=5x−4−42x−30a7=−37x−34
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