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Given $x - y = 3$ and $x y = 10$ , what is $x^{2} + y^{2}$ ?

Class 9Algebraic IdentitiesPolynomials

A19
B29
C-11
D39

Step-by-Step Solution

(x - y)^{2} = x^{2} + y^{2} - 2 x y

, so

x^{2} + y^{2} = 9 + 20 = 29

. (−11 subtracts

2 x y

instead of adding.)

Answer: B) 29

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