Question

3x-7y=10 and xy=-1 find the value of 9x square + 49y square

Answer 1

Hi ,

3x - 7y = 10 --- ( 1 )

xy = -1 ---( 2 )

Do the Square of equation ( 1 ) , we

get ,

( 3x - 7y )² = 10²

( 3x )² + ( 7y )² - 2 × 3x × 7y = 100

9x² + 49y² - 42xy = 100

9x² + 49y² - 42 × ( -1 ) = 100

9x² + 49y² + 42 = 100

9x² + 49y² = 100 - 42

= 58

I hope this helps you.

: )

Answer 2

I have solved it properly
9x²+49y² = 58

if you still have any confusion use comment box.