 |
| ||
| |||
|
| Math Central | Quandaries & Queries |
|
Question from ryan, a parent: solve the equation for x, log2x+log(x+4)=1 how do I do this I keep on getting a crazy decimal answer that doesn't make sense. |
Hi Ryan,
The first step is to realize that since log(a × b) = log(a) + log(b) you can rewrite
log2x + log(x+4) = 1
as
log[2x × (x+4)] = 1 or log(2x2 + 8x) = 1
Now log(10) = 1 so
2x2 + 8x = 10
Solve for x. Make sure you check your answer.
Penny
| ||
| ||
| ||
 |
 |
|
Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.