Question

Q5. If (5x – 2y) = 7 and xy = (-1), find the value of (56+ 2y)? Solution:-​

Answer 1

Step-by-step explanation:

Consider the given equation,

5x−2y=7 and xy=2

We have to find (5x+2y)

2

=?

Now,

(5x−2y)

2

=25x

2

+4y

2

−20xy

7

2

=25x

2

+4y

2

−20×2

25x

2

+4y

2

=89

Now,

(5x+2y)

2

=25x

2

+4y

2

−20xy

(5x+2y)

2

=89−20×2

(5x+2y)

2

=49