5x^2+x-2+0 quadratic formula
You mean \( 5x^2 + x - 2 = 0\)? If so, use a = 5, b = 1, and c = -2 in the quadratic formula.
no i meant 3x^2=2x+7
\[ax^2+bx+c=0 \] is the quadratic formula.
first i put in other form of.... 4x^2-2x-7=0
\[3x^2=2x+7\] So subtract 2x and 7... giving you \[3x^2-2x-7=0\]
hey its 4x^2..sorry 4x^2-2x-7=0
That's fine. Her is a website that will make all of this much easier for you now and in the future. http://www.mathportal.org/calculators/solving-equations/quadratic-equation-solver.php
*Here* My bad, typo.
Okay, sorry. It gives you an explanation. Just though it might help.
i need someone to walk through with me to see where i go wrong
@mathstudent55 0
you have -(-2) but next line as 4.....how?
-(-2) = -1(-2) The product of 2 negative numbers is positive.
yes but how did it double to 4?
Sorry. My mistake. It's 2. You're right.
also
how did 116 go to 29?
I was thinking of the (-2)^2 inside the radical which does turn to 4.
you can factour the three remaining numbers if necessary and leave in division form
Let me do it agian to correct that mistake and to explain better.
4x^2=2x+7
\(4x^2 - 2x - 7 = 0\) \(x = \dfrac{-b \pm \sqrt{b^2 - 4ac}} {2a}\) \(x = \dfrac{-(-2) \pm \sqrt{(-2)^2 - 4(4)(-7)}} {2(4)} \) Ok?
got that as well
2(+,-) sq rt 4-4(-28) divided by 8
\(x = \dfrac{2 \pm \sqrt{4 - (-112)}} {8}\) \(x = \dfrac{2 \pm \sqrt{4 + 112)}} {8}\) \(x = \dfrac{2 \pm \sqrt{116)}} {8}\) Still good?
i see, i have the same
Now we need to take care of the 116 indside the radical. \( x = \dfrac{2 \pm \sqrt{116}} {8} \) I have the same.
\( x = \dfrac{2 \pm \sqrt{4 \times 29}} {8} \) \( x = \dfrac{2 \pm \sqrt{4}\sqrt{29}} {8} \) \( x = \dfrac{2 \pm 2\sqrt{29}} {8} \)
yup
i dont get that
how 116 splits up by four and why
116 = 2 * 2 * 29 = 4 * 29 2 is prime and 29 is prime
ok
The way to simplify a radical is to factor out the largest perfect square you can. The perfect squares that help us here are the squares of the natural numbers: 1, 4, 9, 16, 25, 36, etc.
give me one to try to split
Since 116 = 4 * 29, 4 is the largest perfect square that can be factored out. The you separate the root into : \(\sqrt{116} = \sqrt{4 \times 29} = \sqrt{4}\sqrt{29} = 2\sqrt{29} \)
I will soon. Let's just finsh this problem now. We're almost done.
k
We are here: \(x = \dfrac{2 \pm 2\sqrt{29}} {8} \) Now we factor out a 2 from the numerator and a 2 from the denominator.
1(+,-)sqrt 29 divided by 4
\( x = \dfrac{2(1 \pm \sqrt{29})} {2(4)} \) \( x = \dfrac{2}{2} \times \dfrac{1 \pm \sqrt{29}} {4} \) \( x = \dfrac{1 \pm \sqrt{29}} {4} \) \( x = \dfrac{1 + \sqrt{29}} {4} \) or \( x = \dfrac{1 - \sqrt{29}} {4} \)
Ok?
yes im stuck on one its6 (+,-)sq rt 24 divided by 6
You mean just to simplify it?
This? \( \dfrac{6 \pm \sqrt{24}}{4} \)
no all divided by 6
\(\dfrac{6 \pm \sqrt{24}}{6} \) \(=\dfrac{6 \pm \sqrt{4 \times 6}}{6}\)
is it 3(+.-)sq rt 6 divided by 3?
\(=\dfrac{6 \pm \sqrt{4} \sqrt{6}}{6} \) \(=\dfrac{6 \pm 2 \sqrt{6}}{6} \) \(=\dfrac{3 \pm \sqrt{6}}{3} \) You are correct.
ok the original problem is 3x^2=6x-1 will you check, sorry
\(3x^2=6x-1\) \(3x^2 - 6x + 1 = 0\)
\(x = \dfrac{-b \pm \sqrt{b^2 - 4ac}} {2a}\) \(x = \dfrac{-(-6) \pm \sqrt{(-6)^2 - 4(3)(1)}} {2(3)}\) Ok?
\(x = \dfrac{6 \pm \sqrt{36 - 12}} {6}\) \(x = \dfrac{6 \pm \sqrt{24}} {6}\) This is what you had, so you are correct.
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