The area of a square is 21 more than 10 times its side. If the side of the square is \(x\), which quadratic equation is obtained?
Answer and explanation
Correct answer: \(x^2-10x-21=0\)
If the side of the square is \(x\), its area is \(x^2\). The statement says that the area is 21 more than \(10x\), so \(x^2=10x+21\). Moving all terms to one side gives \(x^2-10x-21=0\). In option B, the sign of the \(10x\) term is incorrect. Exam tip: Translate “more than” by adding to the stated quantity.
Frequently asked questions
What is the correct answer to this question?
\(x^2-10x-21=0\)
Why is this the correct answer?
If the side of the square is \(x\), its area is \(x^2\). The statement says that the area is 21 more than \(10x\), so \(x^2=10x+21\). Moving all terms to one side gives \(x^2-10x-21=0\). In option B, the sign of the \(10x\) term is incorrect. Exam tip: Translate “more than” by adding to the stated quantity.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Introduction to Quadratic Equations.
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