What is the value of the discriminant \(D\) used in the quadratic formula for the equation \(5x^2-10x-3=0\)?
Answer and explanation
Correct answer: 160
Comparing the equation with \(ax^2+bx+c=0\), we get \(a=5\), \(b=-10\), and \(c=-3\). Thus, \(D=b^2-4ac=(-10)^2-4(5)(-3)=100+60=160\). Since \(c\) is negative, the term \(-4ac\) becomes positive. Exam tip: write the sign of \(b\) explicitly before squaring it.
Frequently asked questions
What is the correct answer to this question?
160
Why is this the correct answer?
Comparing the equation with \(ax^2+bx+c=0\), we get \(a=5\), \(b=-10\), and \(c=-3\). Thus, \(D=b^2-4ac=(-10)^2-4(5)(-3)=100+60=160\). Since \(c\) is negative, the term \(-4ac\) becomes positive. Exam tip: write the sign of \(b\) explicitly before squaring it.
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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