What is the value of the discriminant \(D\) for the equation \(x^2-4x+4=0\)?
Answer and explanation
Correct answer: 0
Discriminant is defined by \(D=b^2-4ac\). Here \(a=1,\;b=-4,\;c=4\). Thus \(D=(-4)^2-4\times1\times4=16-16=0\). So the discriminant is 0 and the quadratic has equal (repeated) roots. Option A (4) is incorrect because correct substitution and arithmetic give 0, not 4. Exam tip: always list values of \(a,b,c\) explicitly before computing \(b^2-4ac\) to avoid sign or multiplication mistakes.
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What is the correct answer to this question?
0
Why is this the correct answer?
Discriminant is defined by \(D=b^2-4ac\). Here \(a=1,\;b=-4,\;c=4\). Thus \(D=(-4)^2-4\times1\times4=16-16=0\). So the discriminant is 0 and the quadratic has equal (repeated) roots. Option A (4) is incorrect because correct substitution and arithmetic give 0, not 4. Exam tip: always list values of \(a,b,c\) explicitly before computing \(b^2-4ac\) to avoid sign or multiplication mistakes.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Roots of a Quadratic Equation.
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