Question

X square+ y square if x-y=9 and xy=30

Answer 1

Solution :

It is given that ,

x - y = 9 ----( 1 )

xy = 30 ----( 2 )

We know that ,

x² + y²

= ( x - y )² + 2xy

= 9² + 2×30

[ from (1) and ( 2 ) ]

= 81 + 60

= 141

••••

Answer 2

Answer:

141

Step-by-step explanation:

x - y = 9

Squaring both sides we get :

( x - y )² = 9²

⇒ ( x - y )( x - y ) = 81

We will multiply and simplify to get the value :

⇒ x² - xy - xy + y² = 81

⇒ x² - 2 xy + y² = 81

It is given in the question that :

xy = 30 .

So multiplying with 2 we can get :

2 xy = 60

Hence we can put this value in the original equation to get the result.

⇒ x² + y² - 60 = 81

⇒ x² + y² = 81 + 60

⇒ x² + y² = 141

Hence the value is 141.