What is the factored form of 2x^2 + 20x + 50
So far, I took out 2
Okay, let's see what you got.
And that left me with 2(x^2 + 10 x + 25)
so its 2(x+5)(x+5)
This can be done without the quadratic formula. And @IrisL please don't give away answers,
I thought the answer was 2(x +5)(x + 5) too
However, it isn't one of the listed answers
yea exactly, its 2(x+5)(x+5)
maybe your textbook solution is wrong, you don't need the quadratic formula when it is factorable.
Hmm, what are your solutions listed? Just curious.
(x + 5)(2x − 8) (x − 5)(2x + 8) (x + 5)(2x + 10) (x + 5)(2x − 10)
Oh, simple, just distribute that 5 back in.
Ugh, stop giving away answers!
How would I get to that answer though? Distribute which 5?
oops, sorry I meant 2. Okay, so we have 2(x+5)(x+5) Multiply one of them with the 2, so [2(x+5)](x+5) Do what's in the brackets.
Oh! Okay. So it would be (2x+10)(x+5)
Cools XD
Yup :P
What about polynomials of the third degree?
64^3 +343, to be exact
Anything you can factor out right off the bat?
2 isn't a factor, 3 isn't a factor, 4 isn't a factor... I'm not sure.
7 is a factor of 343, but not 64
Just as a notice, this has one solution..
How do you know?
I graphed it :)
lol cool
So, how would I go about it without any factors? I notice they are both perfect cubes
I think
Oh, I feel dumb now. What we have to do is solve it as a normal equation. So set it equal to zero, and move everything away from x.
\[64x = \sqrt{-343}\]
But wouldn't that be bringing in imaginary numbers?
I meant to put a three as the power
Hold your horses there, you forgot tht 64
*that
lol \[x = \frac{ \sqrt[3]{343} }{ 64 }\]
ANd I meant negative -343
x = 7i/64
Factor out 2, 2(x^2 + 10x + 25) = 2 (x +5)(x+5) or you can write it as 2(x+5)^2. Done.
You can take the cube root of a negative number. It's only even powers that get into the imaginary stuff.
Close: \[64x^3+343=0\] \[64x^3=-343\] \[x^3=-\frac{343}{64}\] \[\LARGE \sqrt[3]{-\frac{343}{64}}\] Now solve it. And when you are taking the cubic root if anything, there are no imaginary numbers, it's just negative. Because \[\LARGE -x^3=-x*-x*-x\]
(Well, negative numbers have complex cube roots too. But I assume you care more about the real one.)
Okay. So - 343/64 = 5.35?
Take the cubic root of each, first.
Oh. so 7/4
*-7/4 but yessssssss
lol okay. So -1.75?
Yea, and that's your one solution.
4x − 7 16x2− 28x + 49 16x2+ 56x + 49 None of the above
So the first one?
Remember what I taught you about working backwards from a solution? x=-7/4
Yes, so far 4x + 7?
Oh. So none of them?
Looks like it. Because it factors into: \[\LARGE (4x+7)(64x^2-112x+196)\]
Wait, no ignore that.
lol k
Hmm, you know what.. I'm stuck >.> Open a new question and see if anyone else can answer it. Sorry. If I get anything I'll let you know.
After distributing, I got that the factors were (4x+7)(16x^2-28x+49)
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