What is the simplified form of (5x-2[3x-{x+4}])?
Answer and explanation
Correct answer: x + 8
First simplify the innermost bracket: 3x - (x + 4) = 3x - x - 4 = 2x - 4. Then, 5x - 2(2x - 4) = 5x - 4x + 8 = x + 8. Hence, x + 8 is correct. The option x - 8 results from handling the sign incorrectly when multiplying 2 by -4. Exam tip: When a bracket is preceded by a minus sign or a multiplier, apply it to every term inside the bracket.
Frequently asked questions
What is the correct answer to this question?
x + 8
Why is this the correct answer?
First simplify the innermost bracket: 3x - (x + 4) = 3x - x - 4 = 2x - 4. Then, 5x - 2(2x - 4) = 5x - 4x + 8 = x + 8. Hence, x + 8 is correct. The option x - 8 results from handling the sign incorrectly when multiplying 2 by -4. Exam tip: When a bracket is preceded by a minus sign or a multiplier, apply it to every term inside the bracket.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Algebraic expressions.
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