Math, asked by hafeezshareef91, 9 months ago

solve log 2 x square - 5 x + 14 is equal to 3​

Answers

Answered by nathantitto26
2
I got the job done today I will see you guys at home tomorrow morning and I can get the
Answered by allysia
1
Here we go,

 log(2 {x}^{2} - 5x + 14 )  = 3 \\  \\  log(2 {x}^{2}  - 5x + 14)  =  log(1000)  \\  \\ 2 {x}^{2}  - 5x + 14 = 1000 \\  \\ 2 {x}^{2} - 5x + 14 - 1000 = 0 \\  \\ 2 {x}^{2}   - 5x - 986 = 0


Now all you gotta do is solve this quadratic equation,


2 {x}^{2}  - 34x + 29x - 986 = 0 \\  \\ 2x(x - 17)   +  29(x  - 17) = 0 \\  \\ (2x + 29)(x - 17) = 0


So one of the values must be 0 to get RHS = 0.

The roots we get then are,

2x + 29 = 0 \\ 2x =  - 29 \\ x =  \frac{ - 29}{2}

and

x - 17 = 0 \\ x = 17


Since logarithms aren't defined for -ve values.
The positive value is taken into consideration and hence x = 17.
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