When 11 is subtracted from a number, the square of the result is 196. If the original number is positive, what is the number?
Answer and explanation
Correct answer: 25
Let the original number be \(x\). Then \((x-11)^2=196\), so \(x-11=\pm14\). This gives \(x=25\) or \(x=-3\). Since the original number is required to be positive, \(x=25\) is correct. In exams, remember to consider both signs when taking the square root and then apply the given condition.
Frequently asked questions
What is the correct answer to this question?
25
Why is this the correct answer?
Let the original number be \(x\). Then \((x-11)^2=196\), so \(x-11=\pm14\). This gives \(x=25\) or \(x=-3\). Since the original number is required to be positive, \(x=25\) is correct. In exams, remember to consider both signs when taking the square root and then apply the given condition.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Word Problems and Applications.
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