A positive number multiplied by the number that is 2 greater than it gives 63. What is the number?
Answer and explanation
Correct answer: 7
Let the number be \(x\). Then \(x(x+2)=63\), so \(x^2+2x-63=0\). Factoring gives \((x-7)(x+9)=0\), yielding \(x=7\) or \(x=-9\). Since the question asks for a positive number, the correct answer is 7. For comparison, choosing 9 gives \(9\times11=99\), not 63. Exam tip: In word problems, first represent the unknown number by \(x\) and express the related number in terms of \(x\).
Frequently asked questions
What is the correct answer to this question?
7
Why is this the correct answer?
Let the number be \(x\). Then \(x(x+2)=63\), so \(x^2+2x-63=0\). Factoring gives \((x-7)(x+9)=0\), yielding \(x=7\) or \(x=-9\). Since the question asks for a positive number, the correct answer is 7. For comparison, choosing 9 gives \(9\times11=99\), not 63. Exam tip: In word problems, first represent the unknown number by \(x\) and express the related number in terms of \(x\).
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Word Problems and Applications.
Student feedback
Was this question useful?
👍 0 Helpful 👎 0 Not helpful
Yes 0% No 0%
0 responsesStudent Reviews
No published reviews yet.
