Solve.
l 2x +1 l = 4
I've never done 'exact; values before any help would be awsome. i've got 3/2 and -5/2, or is it 5/2?
Thanks.
Well, your original answers of $\displaystyle {\frac{3}{2}}$ and $\displaystyle -{\frac{5}{2}}$ are correct.
Basically you have to solve the equation twice. The first time you treat the absolute value as if it were positive, and the second time you treat the absolute value as if it were negative. You do this so you can figure out the positive and negative values that work.
$\displaystyle (2x+1)=4$ and $\displaystyle -(2x+1)=4
$
You can always check your answers by plugging them in:
$\displaystyle | 2({\frac{3}{2}}) + 1 | = 4$
$\displaystyle |4| = 4.$ Correct.
--------------
$\displaystyle | 2(-{\frac{5}{2}}) + 1 | = 4$
$\displaystyle |-4| = 4.$ Correct.
--------------
$\displaystyle | 2({\frac{5}{2}}) + 1 | = 4$
$\displaystyle |6| = 4.$ Wrong.