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Numerical Ability
Algebra
IF X^2+2=2X
THEN THE VALUE OF
X^4-X^3+X^2+2 IS
1. 0
2. 1
3. -1
4. SQ ROOT OF 2
Read Solution (Total 3)
-
- 0
X^2+2=2X
X^2+1-2X = -1
(x-1)^2 =-1
x-1= i where i (iota) is equal to sq root of (-1).
x=1+i
x^2= 1-1+2i=2i
x^4=-4
x^3 = 2i*(1+i)
putting these values in
X^4-X^3+X^2+2
we get
X^4-X^3+X^2+2 =0
- 12 years agoHelpfull: Yes(3) No(3)
- x^4-x^3+x^2+2
x^4-x^3+2x
by adding +2x^2,-2x^2 and -2x,2x
x^4+2x^2-x^3-2x+4x-2x^2
x^2(x^2+2)-x(x^2+2)+4x-2x^2
2x^3+4x-2x^2-2x^2
2x(x^2+2)-4x^2
4x^2-4x^2=0
hence ans 1. 0
- 12 years agoHelpfull: Yes(1) No(2)
- answer is 0.
X^4-X^3+X^2+2=(2X-2)^2-(2X-2)(X)+(X^2+2)
=(2X-2)^2-(2X-2)(X)+(2X)
WE WILL GET, =(2X^2-4X+4)
=2*(X^2-2X+2)
=2*(0)=0.
SO,ANS IS 0. - 12 years agoHelpfull: Yes(0) No(2)
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