Understand the problem: Understand the problem.We need to evaluate the sum of the expression −3x−4n for n ranging from 1 to 5. This is a finite arithmetic series where n is the variable and x is considered a constant within the context of the sum.
Write out the terms: Write out the terms of the sum.The sum can be written out as:(−3x−4×1)+(−3x−4×2)+(−3x−4×3)+(−3x−4×4)+(−3x−4×5)
Simplify each term: Simplify each term in the sum.Now we simplify each term:(−3x−4)+(−3x−8)+(−3x−12)+(−3x−16)+(−3x−20)
Combine like terms: Combine like terms.We can combine the constant terms and the terms with x:(−3x−3x−3x−3x−3x)+(−4−8−12−16−20)This simplifies to:−15x+(−4−8−12−16−20)
Calculate sum of constants: Calculate the sum of the constant terms.Now we calculate the sum of the constant terms:−4−8−12−16−20=−60
Combine x terms: Combine the x terms with the sum of the constant terms.Now we combine the −15x term with the sum of the constant terms:−15x−60
Write final answer: Write the final answer.The final answer is the expression we have obtained:−15x−60
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