Muft Shiksha
Update

Muft Shiksha™ एक 100% Free Education Portal है 🇮🇳, जिसका उद्देश्य Class 9–12 के हर विद्यार्थी तक High-Quality Education को पूरी तरह मुफ्त पहुँचाना है। 🇮🇳 हम मानते हैं कि अच्छी शिक्षा किसी student की आर्थिक स्थिति पर निर्भर नहीं होनी चाहिए। 🇮🇳 हर विद्यार्थी को वही Quality Study Material, MCQs, Quizzes, Exam Preparation, Concept-Based Learning और Bilingual Support मिलना चाहिए, जो आमतौर पर महंगी Coaching या Premium Platforms में मिलता है। Muft Shiksha™ 🇮🇳 इसी सोच के साथ बनाया गया है

Subjects
Class 9MathematicsExploring Algebraic IdentitiesAlgebraic identitiesHardLevel 65
0 reads0 ratings0 helpful

If (x+y=13) and (xy=40), what is the value of (x^2+y^2)?

Advertisement

Answer and explanation

Correct answer: 89

Using the identity \((x+y)^2=x^2+y^2+2xy\), we get \(x^2+y^2=(x+y)^2-2xy\). Therefore, \(x^2+y^2=13^2-2(40)=169-80=89\). Option 169 is only \((x+y)^2\); subtracting \(2xy\) is necessary. Exam tip: when the sum and product are given, start with \((x+y)^2-2xy\).

Related tags

Algebraic IdentitiesSum And ProductSquare Of SumQuadratic ExpressionsClass 9 Mathematics

Frequently asked questions

What is the correct answer to this question?

89

Why is this the correct answer?

Using the identity \((x+y)^2=x^2+y^2+2xy\), we get \(x^2+y^2=(x+y)^2-2xy\). Therefore, \(x^2+y^2=13^2-2(40)=169-80=89\). Option 169 is only \((x+y)^2\); subtracting \(2xy\) is necessary. Exam tip: when the sum and product are given, start with \((x+y)^2-2xy\).

Which subject and chapter does this question cover?

This is a Class 9 Mathematics question. Chapter: Exploring Algebraic Identities. Topic: Algebraic identities.

Was this question useful?

No ratings yetWrite a review / Rate this question

Student Reviews

No published reviews yet.

KEEP PRACTISING

10 more MCQs
  1. 1What is the correct expansion of the identity ( (a+b)^2 )?
  2. 2Choose the correct expansion of the identity ( (x-y)^2 ).
  3. 3The identity ( (p+q)(p-q) ) is equal to what?
  4. 4Which of the following identities represents the factorisation of the difference of two squares?
  5. 5Which of the following identities represents the square of the difference of two terms?
  6. 6In the expansion of which of the following identities is the middle term negative?
  7. 7Which of the following expressions can be written as a product of two binomials using the identity for the difference of squares?
  8. 8Which of the following expressions can be factorised using the identity \(a^2-b^2=(a-b)(a+b)\)?
  9. 9Which algebraic identity is used to factorise a difference of two squares?
  10. 10What is the middle term in ( (3a+2b)^2 )?
Advertisement

Add Muft Shiksha to your Home Screen

In Safari, tap Share, then Add to Home Screen.