Question

If x + y = 8 and xy =15 , find x2 + y2.

Answer 1

GIVEN :
x + y = 8
xy = 15.

Required To Find : x^2 + y^2.

SOLUTION :
we know that,
( x+y )^2 = x^2 + y^2 + 2xy
x^2 + y^2 = ( x + y )^2 - 2xy
= 8^2 - 2×15
= 64 - 30
x^2 + y^2 = 34.


RESULT :
x^2 + y^2 = 34

Answer 2

Answer:

$x^2 + y^2 = 34.$

Step-by-step explanation:

Given : $x + y = 8$

          $xy = 15.$

To Find : $x^2 + y^2.$

Solution:

Identity :

$( x+y )^2 = x^2 + y^2 + 2xy$

$x^2 + y^2 = ( x + y )^2 - 2xy$

$x^2 + y^2= 8^2 - 2×15$

$x^2 + y^2= 64 - 30$

$x^2 + y^2 = 34.$

Thus the value of $x^2 + y^2 = 34.$