If m + n = 13 and mn = 36, what is the value of m² + n²?
Answer and explanation
Correct answer: 97
Use the identity \\(m^2+n^2=(m+n)^2-2mn\\). Thus, \\(m^2+n^2=13^2-2(36)=169-72=97\\), so the correct answer is 97. The value 169 results from using only \\((m+n)^2\\) and omitting the \\-2mn\\) term. Exam tip: When the sum and product of two numbers are given, apply this identity directly.
Frequently asked questions
What is the correct answer to this question?
97
Why is this the correct answer?
Use the identity \\(m^2+n^2=(m+n)^2-2mn\\). Thus, \\(m^2+n^2=13^2-2(36)=169-72=97\\), so the correct answer is 97. The value 169 results from using only \\((m+n)^2\\) and omitting the \\-2mn\\) term. Exam tip: When the sum and product of two numbers are given, apply this identity directly.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Polynomials. Topic: Operations on real numbers and the laws of exponents.
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