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Math help
Fizban140
Registered User, __BANNED USERS regular
Registered User, __BANNED USERS regular
I am trying to do 4x + 3 = 9x - 4
I came out with all sorts of wrong answers and I have no fucking idea what I am suppose to be doing. I am taking an ACT practice test which is seeming to be a huge waste of my time since I don't think I will ever get a decent score on this at all. If I can't even do simple algebra, college will be far too advanced for me.
I just took math 99 and math 100 (college algebra) less than a year ago and I can't even remember how to do this. I seriously think there is something wrong with me, I am some sort of mental disability. I can never remember anything, movies, actors, names of songs, song lyrics, movie quotes, anything. I mean I just fucking took this math class and I can't even work out a simple math problem.
I tried diving both sides by 9x which either leaves me with 4x/9 or 4/9 I am not sure which. I tried adding 4 or subtracting 3 and nothing came out right. Maybe math is just not for me and I should stick to sweeping halls or something, at this point I have no fucking idea what is wrong with me. 12 years can do this shit and I have no concept of how it even works.
I came out with all sorts of wrong answers and I have no fucking idea what I am suppose to be doing. I am taking an ACT practice test which is seeming to be a huge waste of my time since I don't think I will ever get a decent score on this at all. If I can't even do simple algebra, college will be far too advanced for me.
I just took math 99 and math 100 (college algebra) less than a year ago and I can't even remember how to do this. I seriously think there is something wrong with me, I am some sort of mental disability. I can never remember anything, movies, actors, names of songs, song lyrics, movie quotes, anything. I mean I just fucking took this math class and I can't even work out a simple math problem.
I tried diving both sides by 9x which either leaves me with 4x/9 or 4/9 I am not sure which. I tried adding 4 or subtracting 3 and nothing came out right. Maybe math is just not for me and I should stick to sweeping halls or something, at this point I have no fucking idea what is wrong with me. 12 years can do this shit and I have no concept of how it even works.
Fizban140 on
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First thing you should do is remove the variable on the right part of the equation:
3 + 4x + -9x = -4 + 9x + -9x
which leaves you with
3 + -5x = -4
Next you want to get 'x' isolated. So you get rid of the 3.
3 + -3 + -5x = -4 + -3
THIS is where you divide, after 'x' has been isolated.. Divide each side by the value that is situated next to the variable, '-5x'.
-5x / -5 = -7 / -5
leaving us with x = -7 divided by -5. Remember that when dividing two negative signed numbers that the result is always positive:
x = 1.4
can be written as
Another thing is that you were using division wrong. You would use division when you have an expression like the following
Then you would divide by four first, then either add X to the other side, or subtract one.
In any case:
1) Add 4 to both sides which cancels the right hand side #4 out.
2) Subtract 4x from both sides which cancels the left hand side 4x.
Now you can divide both sides by 5.
The right hand side equals 1, so it's just x, and the left hand side equals 1.4.
All the answers in this thread are correct, but I found it easier to get with a visual aid.
The ultimate goal is to remove things until you've solved the equation, however that removal may come about. In this case, after addition, you would divide both sides by 5 to get that 5 off the x. You end up with 7/5 = x, which is the solution to x. And even if it seems superfluous, always do the same operations on both sides. It keeps everything orderly in your head and on the page.
Also remember that 4x + 3 = 9x - 4 is identical to +4x +3 = +9x + -4. Eventually you'll want to get to where you can do this flip in your head. Polynomials will be a pain in the butt otherwise.
I think these were posted in your last math help thread, but just in case:
www.khanacademy.org
www.youtube.com/user/patrickJMT
www.yaymath.org/
And don't waste your time on the "maybe I'm not cut out for math" thing. I could barely add two and two without a panic attack in 2005. No hyperbole. Skills lapse when you don't use them. This goes for any sort of memory. I rarely remember any of that stuff either, but I do when I care about it or spend time considering a fact.
It's why I can design a network on a napkin, but couldn't make a network cable to save my life.
So if something says 3x+4 = 5-2x, you'll want to get all the constants on one side and all the variables on the other.
You can take this a step further with multiple variables. You'll be solving in terms of something.
So if your equation is: 3x+y = 42+2y, you could solve that in terms of x by moving everything to the other side of the equals. Terms of y, same issue, just move x to the other side.
Most people make the misconception that math is some magical talent that savants get immediately and is impossible for everyone else. It's a skill like any other and you just have to practice it.
Don't give up!
This.
If you're like most humans then you don't get math without an epic struggle greater than anything in mythology. For you and most of us, math is a bitch. But it's probably the best thing you'll ever invest time in.
Most math resources are made for the 1% who get it easily, so it skews our perspective. It seems hard because it's not like other subjects where there's a ton of help suitable for every kind of person's learning style.
Basic math will also let you see right through most marketing gimmicks. It's very nice when you work out what "25% more" means and realize that you just put yourself above most of the populace by checking a claim.
In addition to the advice from the other posters, I wanted to leave you with a rule of thumb...it's usually a bad idea to divide both sides of an equation by a variable (like, in your case, dividing by x). At best it makes the equation more annoying to solve, at worst you eliminate a solution that should be a part of your answer.
Dividing by a number (like 9) is perfectly fine as long as you make sure to divide EVERY term in the equation by that number. This is a common mistake I see from my students all the time.
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And a more simplified version of this advice: If an operation makes things more complicated, you more often than not shouldn't be doing it at that step.
It took about 30 worksheets from math.com before I could simplify an expression without any errors. There's a point where you've practiced enough to pass between rote memorization of a process and real comprehension. Once you get the latter, you're not likely to forget, and it's easy to relearn if you do.
With genuine comprehension, you don't worry about steps, you just do it. It's like tying shoes.
Eventually I'm going to go through all the math things on Khan Academy so I can make sense of the fun (advanced) stuff.
It always came easy to me. Plus I teach it, so I guess that's sort of cheating.
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It's not memorization, it's a fundamental understanding of mathematics.
Note: this fundamental understanding comes from lots of practice.