If (x=-3), what is the value of (x^2-2x+4)?
Answer and explanation
Correct answer: 19
Substitute -3 for x: \(x^2-2x+4=(-3)^2-2(-3)+4\). This gives \(9+6+4=19\), so 19 is correct. Option 7 may result from incorrectly treating \(-2(-3)\) as -6; the product of two negative numbers is positive. Exam tip: Always use brackets when squaring or substituting a negative value.
Frequently asked questions
What is the correct answer to this question?
19
Why is this the correct answer?
Substitute -3 for x: \(x^2-2x+4=(-3)^2-2(-3)+4\). This gives \(9+6+4=19\), so 19 is correct. Option 7 may result from incorrectly treating \(-2(-3)\) as -6; the product of two negative numbers is positive. Exam tip: Always use brackets when squaring or substituting a negative value.
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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