- #1
greg_rack
Gold Member
- 363
- 79
- Homework Statement
- $$a-2=-\sqrt{a^2-4}$$
- Relevant Equations
- none
For solving this equation I must take elevate to the square of each member, resulting in:
$$(a-2)^2=a^2-4 \rightarrow a=2$$
Now, the thing I noticed and don't get is that if you simplify a ##(a-2)## factor, the equation becomes impossible:
$$a-2=a+2$$
It must be a stupid thing which I'm missing...
$$(a-2)^2=a^2-4 \rightarrow a=2$$
Now, the thing I noticed and don't get is that if you simplify a ##(a-2)## factor, the equation becomes impossible:
$$a-2=a+2$$
It must be a stupid thing which I'm missing...