Question

if a+b=72 and ab=1280 then find a-b
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Answer 1

a+b = 72

ab= 1280

${(a + b)}^{2} = {a}^{2} + {b}^{2} + 2ab \\ {72}^{2} = {a}^{2} + {b}^{2} + 2 \times 1280 \\5184 = {a}^{2} + {b}^{2} + 2560 \\{a}^{2} + {b}^{2} = 5184 - 2560 \\ {a}^{2} + {b}^{2} = 2624 \\ \\ {( a - b)}^{2} = {a}^{2} + {b}^{2} - 2ab \\ {( a - b)}^{2} = 2624 - 2560 \\ {( a - b)}^{2} = 64 \\ (a - b) = \sqrt{64 } \\ (a - b) = 8$

Hope this will help....