Question

20) If x - y =3, xy = 28, find x² + y squqre?
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Answer 1

x=7 and y=4 put value

49+4=53

Answer 2

Hey,

$x - y = 3 \: and \: xy = 28 \\ \\ now \\ x {}^{2} + y {}^{ 2 } \\ adding \: and \: \: subtracting \: 2xy \\ = (x - y) {}^{2} + 2xy \\ = (3) {}^{2} + 2 \times 28 \\ = 9 + 56 = 65$

I hope it helps you!!!