Question 2.

The sum of all possible values of x satisfying the equation 24x222x2+x+16+22x+30=02^{4 x^2}-2^{2 x^2+x+16}+2^{2 x+30}=0, is

A
32\frac{3}{2}
B
52\frac{5}{2}
C
12\frac{1}{2}
D
3

Question Explanation

Text Explanation

It is given that 24x222x2+x+16+22x+30=0 2^{4x^2} - 2^{2x^2+x+16} + 2^{2x+30} = 0 , which can be written as:

=> (22x2)222x22x+1521+(2x+15)2=0 \left(2^{2x^2}\right)^2 - 2^{2x^2} \cdot 2^{x+15} \cdot 2^1 + \left(2^{x+15}\right)^2 = 0

=> (22x22x+15)2=0 \left(2^{2x^2} - 2^{x+15}\right)^2 = 0

=> 22x22x+15=0 2^{2x^2} - 2^{x+15} = 0 (Since (ab)2=0ab=0 (a-b)^2 = 0 \Rightarrow a-b = 0 )

=> 2x2=x+15 2x^2 = x + 15

=> 2x2x15=0 2x^2 - x - 15 = 0

=> 2x26x+5x15=0 2x^2 - 6x + 5x - 15 = 0

=> 2x(x3)+5(x3)=0 2x(x-3) + 5(x-3) = 0

=> (2x+5)(x3)=0 (2x+5)(x-3) = 0

Hence, the possible values of x are 52 -\frac{5}{2} , and 3, respectively.

Therefore, the sum of the possible values is (352)=12 \left(3 - \frac{5}{2}\right) = \frac{1}{2}

The correct option is C

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