Math, asked by siddharth2005211, 1 year ago

2^2x+3 -9*2^x+1=0 find X

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Answered by ihrishi
70

Answer:

 {2}^{2x + 3}  - 9 \times  {2}^{x}  + 1 = 0 \\  {2}^{2x}  \times  {2}^{3}  - 9 \times  {2}^{x}  + 1 = 0 \\ 8 \times  ({2}^{x} )^{2}  - 9 \times  {2}^{x}  + 1 = 0 .....(1) \: \\ let \:  {2}^{x}  = y  \\  \therefore \: equation \: (1) \: reduces \: to:  \\ 8 {y}^{2}  - 9y + 1 = 0 \\ 8 {y}^{2}  - 8y  - y+ 1 = 0  \\ 8y(y - 1) - 1(y - 1) = 0 \\ (y - 1)(8y - 1) = 0 \\ y - 1 = 0 \: or \: 8y - 1 = 0 \\  y = 1 \: or \: y =  \frac{1}{8}  \\  \because \: at \: y = 1 \: it \: is \: not \: possible \: to \\ find \: the \: value \: of \: x \: as \: bases \: will \\ be \: different :  \\ so \: at \:  \:  \:  \:  \:  \: y =  \frac{1}{8}  \\  {2}^{x}  =  \frac{1}{8}  \\  {2}^{x}  =  \frac{1}{ {2}^{3} }  \\  {2}^{x}  =  {2}^{ - 3}  \\ x =  - 3

Answered by am2006
29

Hope it helps....

please mark as "BRAINLIST". ...

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