Question

a2+b2=9,ab=8,then a+b=?​

Answer 1

Step-by-step explanation:

$\huge\underline\mathfrak\blue{Given:-}$

$a {}^{2} + b {}^{2} = 9 \\ ab = 8$

$\huge\underline\mathfrak\blue{Find out:-}$

$value \: of \: \: \: a + b$

$\huge\underline\mathfrak\blue{Solution:-}$

$a {}^{2} + b {}^{2} = (a + b) {}^{2} - 2ab \\ or \: \: \: \: \: 9 = (a + b) {}^{2} - 2 \times 8 \\ or \: \: \: \: \: 9 = (a + b) {}^{2} - 16 \\ or \: \: \: \: \: (a + b) {}^{2} - 16 = 9 \\ or \: \: \: \: \: (a + b) {}^{2} = 9 + 16 \\ or \: \: \: \: \: (a + b) {}^{2} = 25 \\ or \: \: \: \: \: (a + b) = \sqrt{25} \\ so \: \: \: \: \: a + b = 5$

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