If 4x2 + 3y2 = 28, xy = 4 (x, y > 0)
find 7x3 + y2 + 3.
Answer & explanation
Correct answer: option 4
By Putting x = 2 and y = 2
These values are satisfying the equations:
⇒ 4x2 + 3y2 = 28
⇒ 4(2)2 + 3(2)2 = 28
⇒ 28 = 28
Put these values and find:
⇒ 7x3 + y2 + 3. = 7(2)3 + (2)2 + 3= 56 + 4 + 3 = 63