Help with algebraic equations

Please explain how to do these! Thank you.

b+3/e=f/2 solve for e.

a/b=c/d solve for d.

I have a test on this tomorrow, so please help me.

Well basically you need to get the letter you want on one side and all the other stuff on the other. (remember what you do to one side, do to the other.)

For example, solve for 'e' question:

*e b+3/e=f/2 *e

b+3=f/2(e)
*2 *2

2b+6=f(2e)
/f /f
2b+6/f=2e
(2b+6/f)/2=e

2.) a/b=c/d solve for d.

a/b=c/d
*d *d
a/b*d=c
*b *b
ad=cb
/a /a
d=cb/a

hope this helped! (remember what you do to one side, do to the other.)

3/e=f/2-b
1/e=(f/2-b)/3
(1/e)^-1=((f/2-b)/3)^-1
e=3/(f/2-b)


a/b=c/d
b/a=d/c
d/c=b/a
d=cb/a