Thursday, February 25, 2010

`x^2 - x = log_5(25)` Solve for x or b

`x^2-x=log_5 (25)`


First, simplify the right side of the equation. To do so, factor 25.


`x^2 - x = log_5 (5^2)`


Then, apply the logarithm rule `log_b (a^m) = m * log_b (a)` .


`x^2 - x = 2 * log_5 (5)`


Take note that when the base and argument of the logarithm are the same, its resulting value is 1 `(log_b (b)=1)` .


`x^2 - x = 2 * 1`


`x^2 - x = 2`


To solve quadratic equation, one side should be zero.


`x^2 - x -2 =0`


Then, factor the left side.


`(x - 2)(x + 1)=0`


Set each factor equal to zero. And isolate the x.


`x - 2 = 0`


`x=2`



`x + 1=0`


`x=-1`



Therefore, the solution is `x = {-1,2}` . 

No comments:

Post a Comment

Thomas Jefferson's election in 1800 is sometimes called the Revolution of 1800. Why could it be described in this way?

Thomas Jefferson’s election in 1800 can be called the “Revolution of 1800” because it was the first time in America’s short history that pow...