Mark the Correct alternative in the following:
The number of real roots of the equation 
is
given (x2+2x)2-(x+1)2-55=0
[(x2 +2x +1) -1] 2 -(x +1)2 -55 =0
(x +1)⁴ -2(x +1)2 +1 -(x +1)2 -55 =0
(x+1)⁴ -3(x +1)2 -54 =0
let (x +1)2= r
r2 -3r -54 =0
r2 -9r +6r -54 =0
r( r -9) +6(r -9) =0
r = -6 , 9
but ( x+1)2 ≥ 0 so, (x+1)2 ≠ -6
so, (x +1)2 = 9
x + 1 = ± 3
x = -1 ±3
x = -4, and 2 .
1