Question

The sum of two squares of two numbers is 20 and their product is 2 .Find the difference between them

• A. $\pm 4$
• B. $\pm 16$
• C. 20
• D. 18

Answer 1

The correct option is A

$\pm 4$

Let the two numbers be x and y.

Given: $x^2+y^2$ = 20 and xy = 2

We know the identity $(x-y{)}^2$ = $x^2$ + $y^2$ - 2xy

Which gives $(x-y{)}^2$ = 20 - 4

$(x-y{)}^2$ = 20 - 4

=16

$x-y$ = $\pm 4$