If (x -1)2 = 400, which of the following could b the value of x-5 ?
সমাধান
সঠিক উত্তর: Option C
(x -1)2 = 400
or, (x -1)2 = (20)2
or, (x -1) = (+-)20
or, x = (+-)20 + 1 = +21 or -19
Now,
x - 5 = +21 - 5 (Taking the positive value)
= +16
or,
x - 5 = -19 - 5 = -24