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I'm studying for Intermediate Algebra - why am I so confused by the powers?
Right now I'm studying Common Factors and Factoring by Grouping - for some reason when I see (example problem - 15x^5 + 25x^3 +20x) I get so confused.
What is the rule here when you see the powers (5 & 3)?
powers / exponents - I think you know what I mean *
And that is because 5 goes into 15, 25, and 20 - Correct? then just use the variable with the smallest power?
Chris - I got 5x(3x^4+5x^2+4) and MyMathLab accepted it but I think I'm on the right path :)
3 Answers
- Anonymous6 years ago
whats up HOMIIEEEEE?!?!
Anyway... I totalllyyyyy forget what factoring by grouping is lol Ans that's not good because I'm a math major. HOWEVER.!.!.!.... for this example problem you have so kindlyyyy supplied for me, I should tell you that the FIRST thing you should see is that you can factor a 5x (this is the greatest common factor of this trinomial btw) out of this trinomial.... Which will leave you with something that looks like this:
(5x) (3x^4 + 5x^2 + 2)<--------THAT 2 IS A 4 MY BAD!!!! Hahah. So you got it 👍
If this dosent help you then please elaborate on the factoring by grouping thing... Lol and I'm sure I can help.
- HuhLv 66 years ago
Powers are those superscripts. It's a way of maximizing multiplication. Let us work our way up, okay. Multiplication is simply an expansion of addition, and division is an expansion of subtraction.
2(3) = 2 + 2 + 2 ... or 3 + 2 = 6
3(4) = 3 + 3 + 3 + 3 ... or 4 + 4 + 4 = 12
However, what if we took multiplication up a notch:
2^(3) = 2 * 2 * 2 = 8.
That is, we multiply 2 three times.
I will change the power, just so you get the picture:
3^2 = 3 * 3 = 9. That is, multiply 3 twice
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What does x^3 mean, it meas to multiply x by itself three times. That's great, but what is x?
5 * x^3 = 320
(5 * x^3) / 5 = 320 / 5
x^3 = 64
Now divide 64 into it's multiples to understand the cubic root, so the numbers 1 - 9.
64 / 2 = 32 ; 32 / 2 = 16 ; 16 / 2 = 8 ; 8 / 2 = 4 ; 4 / 2 = 2
So the expression makes sense:
x^3 = (2 * 2 * 2) * (2 * 2 * 2)
It's cubic so I used parentheses to grouped the 2's into sets of 3's.
If we consider each group of the same number as one number and we multiply the sets, we get:
x = 2 * 2 = 4
Sure enough ... x^3 = 64 is the same as 4^3 = 4 * 4 * 4 = 64
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But that was a waste of your time, you should have just taken the cubic root:
(x^3)^(1 / 3) = 64^(1 / 3)
x^(3 * 1 / 3) = 4
x^1 = 4
x = 4
How about another:
√(x + 4) = 16
Cancel the square root operation to both sides:
[√(x + 4)]^2 = (16)^2
x + 4 = 256
Subtract 4 to both sides:
x + 4 - 4 = 256 - 4
x = 252
Also,
x^2 = 9
√x^2 = √9
x = ± 3
Thus, x = 3, and x = -3
This is because 3 * 3 = 9, and - 3 * -3 = 9
It wouldn't work for the cubic example that I used earlier because only ...
positive * positive * positive = positive
Source(s): Then if or when you get into calculus, you will learn how to expand exponents. - ?Lv 76 years ago
You have to use the lowest power of x in your GCF. There is an x (to the 1) so we use that. The GCF is 5x ☜