Question

If x-y= 43 , xy = 15.
Find x²+y²

Answer 1

Step-by-step explanation:

Here,

x-y=43

(x-y)(x-y)=43×43=1849

=x×x+y×y-2xy=1849

therfore,

answer=

=1849+2xy

=1849+2×15

=1849+30

=1879

Answer 2

$x^2+y^2$ = 1879

Step-by-step explanation:

We have:

x - y = 43 , xy = 15

To find, the value of $x^2+y^2$ = ?

∴ x - y = 43

Squaring both sides, we get

$(x - y)^2$ = $43^2$

⇒ $x^2+y^2$ - 2xy = 1849

Using the algebraic identity,

$(a - b)^2$ = $a^2+b^2$ - 2ab

⇒ $x^2+y^2$ = 1849 + 2xy

Put  xy = 15, we get

$x^2+y^2$ = 1849 + 2(15)

⇒ $x^2+y^2$ = 1849 + 30

⇒ $x^2+y^2$ = 1879

∴ $x^2+y^2$ = 1879