What is the value of the discriminant (D ) used in the quadratic formula for (3x^2-6x-2=0 )?
Answer and explanation
Correct answer: 60
Comparing the equation with (ax^2+bx+c=0 ), we get (a=3,b=-6,c=-2 ). Thus, (D=b^2-4ac=(-6)^2-4(3)(-2)=36+24=60 ). Since (c ) is negative, the term (-4ac ) becomes positive, so 24 must be added to 36 rather than subtracted. Exam tip: identify (a,b,c ) with their signs before applying the formula.
Frequently asked questions
What is the correct answer to this question?
60
Why is this the correct answer?
Comparing the equation with (ax^2+bx+c=0 ), we get (a=3,b=-6,c=-2 ). Thus, (D=b^2-4ac=(-6)^2-4(3)(-2)=36+24=60 ). Since (c ) is negative, the term (-4ac ) becomes positive, so 24 must be added to 36 rather than subtracted. Exam tip: identify (a,b,c ) with their signs before applying the formula.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Methods of Solving Quadratic Equations.
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