Q. Which expression is equivalent to 387−641?Choose 1 answer:(A) 387+(−641)(B) 387+(641)(C) 641−(387)(D) −641+(−387)
Understand the problem: Understand the problem.We need to find an expression equivalent to the given expression 3(87)−6(41). This involves understanding subtraction of fractions.
Convert to improper fractions: Convert mixed numbers to improper fractions.387 is already an improper fraction, so it remains the same.641 as an improper fraction is 6×4+1=425.
Rewrite with improper fractions: Rewrite the original expression using the improper fraction for 6(41). The original expression 3(87)−6(41) becomes 3(87)−425.
Find common denominator: Find a common denominator for the fractions.The common denominator for 8 and 4 is 8.
Convert to common denominator: Convert the second fraction to have the common denominator.To convert 425 to have a denominator of 8, we multiply both the numerator and the denominator by 2, which gives us 850.
Rewrite with common denominator: Rewrite the expression with the common denominator.Now the expression is 3(87)−850.
Subtract fractions: Subtract the fractions.Subtracting the fractions with the common denominator gives us (3×7−50)/8, which simplifies to (21−50)/8.
Simplify result: Simplify the result.(21−50)/8 simplifies to −29/8, which is an improper fraction.
Convert to mixed number: Convert the improper fraction back to a mixed number. −829 as a mixed number is −385.
Find equivalent expression: Look for the equivalent expression among the choices.The equivalent expression to 3(87)−6(41) is −3(85), which is not directly listed among the choices. However, we can express this as the addition of a negative, which is choice (A) 3(87)+(−6(41)).
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