# Thread: Uhg... I thought I did this last year -- basic algeblah

1. ## Uhg... I thought I did this last year -- basic algeblah

$\displaystyle 4 - 1/2a$ $\displaystyle = 7/2 - a$

Could someone please work this for me? This is not the actual problem, but part of it, and I cannot remember what to do with the silly fractions next. There is something you do with the fractions... but my brain needs refreshing lol

2. Originally Posted by Melancholy
$\displaystyle 4 - 1/2a$ $\displaystyle = 7/2 - a$

Could someone please work this for me? This is not the actual problem, but part of it, and I cannot remember what to do with the silly fractions next. There is something you do with the fractions... but my brain needs refreshing lol
do you mean $\displaystyle \frac {4 - 1}{2a} = \frac {7}{2 - a}$? because that's not what you wrote

3. Ermm.... no.... I mean

Four minus half of a = seven seconds minus a

4 - [the fraction 1/2]a = [the fraction 7/2] - a

Does that make sense? Sorry!

4. Originally Posted by Melancholy
Ermm.... no.... I mean

Four minus half of a = seven seconds minus a

4 - [the fraction 1/2]a = [the fraction 7/2] - a

Does that make sense? Sorry!
ok. first, get all the a's on one side and all the constants on the other:

$\displaystyle 4 - \frac a2 = \frac 72 - a$

$\displaystyle \Rightarrow a - \frac a2 = \frac 72 - 4$ ........simplify each side

$\displaystyle \Rightarrow \frac a2 = - \frac 12$ ...........multiply both sides by 2

$\displaystyle \Rightarrow a = -1$

This is my 4th post!!!!!

5. Thank you! And happy 4,000th post!!! Wow, that's a biiiiig step! On my forum, an admin just celebrated his 10,000th........ I know.... lol!