solving equations

dali120

New member
Joined
Jul 22, 2007
Messages
1
I really don't understand Algebra! Here are a few problems I can't figure out how to do:

1.) 3 (2y - 3) = 27 the answer I got for this was 9...I don't understand how it is 6

2.) 40 = 5 (3x + 2) have no idea how to solve this

3.) 7/8a - 1/4 + 1/2a = 3/4 + a this is how far I got. I am not sure this is right:
8/1 (7/8a + - 1/4 + 1/2a = 3/4 + a)
56/8a - 8/4 + 8/2a = 24/4 + a
7a - 2 + 4a = 6 + a am I at least on the right track?

4.) 8x - 1 = 23 - 4x I don't understand how to do the math on both sides.
5.) 6x + 3 = 2x +11

6.) y = 5x, solve for x x = y/5 this makes no sense to me.
7.) y = 13 + x solve for x x = y - 13 I don't understand how??

I am a logical thinker, is it possible I am thinking to hard in to these problems? There are many more I don't understand, but I'll just try to understand these to start. Thanks for your help!
 

stapel

Super Moderator
Staff member
Joined
Feb 4, 2004
Messages
15,943
1) How did you get your answer? When you plugged in their answer (y = 6), what did you get for the value of 3(2y - 3), if not 27? :?:

2) How did you solve (1), if you have "no idea how to solve this" same sort of exercise? :shock:

3) Your formatting is ambiguous. Do you mean any of the following?

. . . . .7/(8a) - 1/4 + 1/(2a) = 3/4 + a

. . . . .7/(8a) - 1/4 + 1/(2a) = 3/(4 + a)

. . . . .7/(8a - 1/4) + 1/(2a) = 3/4 + a

. . . . .7/(8a - 1/4) + 1/(2a) = 3/(4 + a)

. . . . .(7/8)a - 1/4 + (1/2)a = 3/4 + a

Or something else? :|

4) I'm sorry, but I don't understand your comment about "the math on both sides". If you weren't operating on both sides of the equations in (1) through (3), what process were you using? Please be specific. :!:

5) See (4). :wink:

6) I will guess that you have never seen one-step linear equations, because this is much simpler than the exercises above. Short version: If 15 = 5x, when what does x equal? How did you get that? Now do the same thing with y = 5x. Long version: web lessons 8-)

7) See (6). Hint: If 16 = 13 + x, what does x equal? How did you get that? Now do the same thing with y = 13 + x. Long version: web lessons

Hope that helps a bit! :D

Eliz.
 

Denis

Senior Member
Joined
Feb 17, 2004
Messages
1,442
dali120 said:
...I am a logical thinker, is it possible I am thinking to hard in to these problems?
"Thinking too hard" is not your problem;
your problem is you don't know the simple basics.

If 2 apples and 3 bananas cost 85 cents, and the price of a banana is 15 cents,
you can calculate the price of an apple, right?
That's same as:
2a + 3b = 85
b = 15
Solve for a

Are you in school or studying on your own?
 
Top