If x + y = 9, xy = 20find: x^2 - y^2. - Vidyadip

Question

If $x + y = 9, xy = 20$find: $x^2 - y^2.$

✓

Answer

$x + y = 9, xy = 20$
We know,
$(x - y) (x + y)$
$= x^2 - y^2$
$\Rightarrow x^2 - y^2$
$= (±1) (9)$
$= ±9.$

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