If y = y x satisfies the differential equation 8 x 9 + x d y = 4 + 9 + x - 1 d x and x > 0 ,   y 0…

If y=yx satisfies the differential equation 8x9+xdy=4+9+x-1dx and x>0, y0=7, then y256=
  1. 80
  2. 3
  3. 16
  4. 9

Solution

y=18 dx4+9+x . x . 9+x

Put  9+x=t    dxx . 9+x=4dt

 y=48 dt4+t

y= 4+t+C

yx= 4+9+x+C

At   x=0:y0= 7     C=0

 yx= 4+9+ x

y256=3

Asked in: JEE Advanced 2017 (Paper 2)

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