What is obtained after simplifying (4r^2-6r^2+5r)?
Answer and explanation
Correct answer: -2r^2+5r
Here, 4r^2 and -6r^2 are like terms, so their coefficients are combined: 4-6=-2. Thus, 4r^2-6r^2=-2r^2, while 5r remains unchanged because it has a different power of r. Therefore, the simplified expression is -2r^2+5r. In option D, the sign of 5r is incorrectly changed. Exam tip: Combine only terms with the same variable raised to the same power.
Frequently asked questions
What is the correct answer to this question?
-2r^2+5r
Why is this the correct answer?
Here, 4r^2 and -6r^2 are like terms, so their coefficients are combined: 4-6=-2. Thus, 4r^2-6r^2=-2r^2, while 5r remains unchanged because it has a different power of r. Therefore, the simplified expression is -2r^2+5r. In option D, the sign of 5r is incorrectly changed. Exam tip: Combine only terms with the same variable raised to the same power.
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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