Question

5x-7y=19 and xy=-2 then,find the value of 25x²+49y²​

Answer 1

Solution :

25x² + 49y² =  (5x - 7y)² + 70xy

⇒ 25x² + 49y² = (19)² + 70(-2)

⇒ 25x² + 49y² = 361 - 140

⇒ 25x² + 49y² = 221

∴ The of 25x² + 49y² is 221.

Hope this help : )