Question

If 2x-5y = 8 and xy= 4, find the value of 4x^2 +25y^2

Answer 1

Answer:

Correct option is

A

40

Given

2x+3y=8 and xy=2,

formula,

(a+b)

2

=a

2

+b

2

+2ab

∴(2x+3y)

2

=4x

2

+9y

2

+2(2x)(3y)

(2x+3y)

2

=4x

2

+9y

2

+12xy

8

2

=4x

2

+9y

2

+12(2)

∴4x

2

+9y

2

=64−24=40