When 256 is subtracted from the square of a number, the result is 1040. What is the positive number?
Answer and explanation
Correct answer: 36
Let the number be \(x\). According to the statement, \(x^2-256=1040\), so \(x^2=1296=36^2\). Thus, \(x=36\) or \(x=-36\), but the positive number is \(36\). For instance, choosing 34 gives \(34^2-256=900\), so it is not correct. Exam tip: Interpret “subtracted from the square” as \(x^2-\text{given value}\).
Frequently asked questions
What is the correct answer to this question?
36
Why is this the correct answer?
Let the number be \(x\). According to the statement, \(x^2-256=1040\), so \(x^2=1296=36^2\). Thus, \(x=36\) or \(x=-36\), but the positive number is \(36\). For instance, choosing 34 gives \(34^2-256=900\), so it is not correct. Exam tip: Interpret “subtracted from the square” as \(x^2-\text{given value}\).
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.
