Question

if X square + y square = 29 and xy = 10 then find the value of x cube minus y cube​

Answer 1

Answer:

We know

$(x - y) {}^{2} = {x }^{2} + {y}^{2} - 2xy \\ \\ (x - y) {}^{2} = 29 - 2(10) = 9 \\ \\ (x - y) = \pm\sqrt{9} = \pm \: 3$

Now

${x}^{3} - {y}^{3} = (x - y)( {x}^{2} + {y}^{2} + xy) \\ \\ = \pm3(29 + 10) \\ \\ = \pm \: 117$