If x – y = 18 and xy = 13, then the value of x2 – y2 = ?​

1 thought on “<br />If x – y = 18 and xy = 13, then the value of x2 – y2 = ?​”

1. Answer:

   [tex]( {x +y)}^{2} – {(x – y)}^{2} = 4xy \\ {(x + y)}^{2}- {(18)}^{2} = 4(13) \\ ( {x + y)}^{2} = 324 + 52 \\ ( {x + y)}^{2} = 376 \\ (x + y) = 2 \sqrt{94} \\ {x}^{2} – {y}^{2} = (x + y)(x – y) \\ = (2 \sqrt{94} )(18) \\ {x}^{2} – {y}^{2} = 36 \sqrt{94} [/tex]

   Reply