When 3 is added to a number, the square of the resulting number is 100. What is the number when the positive square root is taken?
Answer and explanation
Correct answer: 7
Let the number be \(x\). Then \((x+3)^2=100\). Taking the positive square root gives \(x+3=10\), so \(x=7\). The negative square root would give \(x=-13\), but the question specifically asks for the positive square root. Exam tip: When solving a squared equation, consider both roots and then apply the condition given in the question.
Frequently asked questions
What is the correct answer to this question?
7
Why is this the correct answer?
Let the number be \(x\). Then \((x+3)^2=100\). Taking the positive square root gives \(x+3=10\), so \(x=7\). The negative square root would give \(x=-13\), but the question specifically asks for the positive square root. Exam tip: When solving a squared equation, consider both roots and then apply the condition given in the question.
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.
