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The roots of 22x−10×2x+16=02^{2x}-10×2^x+16=022x−10×2x+16=0​ are:
Question

The roots of 22x10×2x+16=02^{2x}-10×2^x+16=0​ are:

A.

2, 3

B.

1, 8

C.

2, 8

D.

1, 3

Correct option is D

Given:

22x10×2x+16=02^{2x} - 10 \times 2^x + 16 = 0

Solution:

Let y=2xy = 2^x​, so 22x=y22^{2x} = y^2​​

Rewritten Equation:

y210y+16=0y^2 - 10y + 16 = 0​​

Solve quadratic equation using factorization:

y210y+16=(y2)(y8)=0y^2 - 10y + 16 = (y - 2)(y - 8) = 0​​

Roots: y=2 or y=8.y = 2 \, \text{or} \, y = 8.​​

Since y = 2x

2x=2 x=1, 2x=8 x=32^x = 2 \implies x = 1, \\ \ \\ 2^x = 8 \implies x = 3 ​​

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