ok I'm lst on quadratic equation. Can someone help me step by step.use quadratic formula to solve the equation

Question

2x^+ 8x + 3 = O
This is how far I got: x^2 + 8x + 3/2 = 0
x^2 + 8x = -3/2
but not sure how to proceed from here. the book is really confusing.

ok i messed up the original equation its: 2x^2 + 8x +3 = 0 not 2x

my email is [e-mail]

Answer 1

Using quadratic formula:-
2x² + 8x + 3 = 0
x = [ - 8 ± √(64 - 24) ] / 4
x = [ - 8 ± √(40) ] / 4
x = [ - 8 ± 2√(10) ] / 4
x = [ - 2 ± (1/2) √(10) ]
x = [ - 2 ± (1/2)√(5)√(2)
x = [ - 2 ± √(5) / (√2) ]
x = [ - 2 ± √(5/2) ]

Using completing the square:-
2(x² + 4x + 3/2) = 0
2(x² + 4x + 4 - 4 + 3/2) = 0
(x² + 4x + 4) - 5/2 = 0
(x² + 4x + 4) = 5/2
(x + 2)² = 5/2
x + 2 = ±√(5/2)
x = - 2 ± √ (5/2)

Answer 2

How did u get from "2x^+ 8x + 3 = O" to "x^2 + 8x + 3/2 = 0
"?

Anyway, ill just go on from "x^2 + 8x + 3/2 = 0"..

Now the general form of a quadratic equation is as follows:

ax^2 + bx + c = 0 where a, b, c are constants

the quadratic formula states that:

x = [ -b ± √(b^2 - 4ac) ] / 2a

In your case, a = 1, b = 8, c = 3/2.
So now you just gotta sub it in:

x = [ -(8) ± √(64 - 4*1*3/2) ] / 2*1
= [ -8 ± √(64 - 6) ] / 2
= [ -8 ± √(58) ] / 2
= (-8-√58) / 2 or (-8+√58) / 2

Answer 3

Quadratic equation is : [-b ± ?(b² - 4ac)] / 2a some thing with sq. roots that could want to't be factored i will basically be leaving as is. a million. 3x² - 0x - 12 = 0 [ 0 ± ?(0² - 4(3)(-12))] / 2(3) [0 ± ?(0 + 100 and forty four)] / 6 ± ?(100 and forty four)] / 6 ±12/ 6 ±2 2. 4x² + 9x + 5 = 0 [-b ± ?(b² - 4ac)] / 2a [-9 ± ?(9² - 4(4)(5))] / 2(4) [-9 ± ?(80 one - 80)] / 8 [-9 ± ?a million]8 [-9 ± a million] / 8 both -a million or -(5/4) 3. 5x² - 6x - 4 = 0 [6 ± ?((-6)² - 4(5)(-4))] / 2(5) [6 ± ?(36 + 80] / 10 [6 ± ?(116)] / 10 [6 ± (?2 * ?2 * ?29)] / 10 [6 ± 2?29] / 10 [3 ± ?29] / 5 4. -x² + x + a million [-a million ± ?(a million² - 4(-a million)(a million))] / 2(-a million) [-a million ± ?(a million + 4)] / -2 [-a million ± ?5] / -2 5. 2x² + 5x + 0 [-5 ± ?(5² - 4(2)(0))] / 2(2) [-5 ± ?(25 - 0)] / 4 [-5 ± ?25] / 4 [-5 ± 5] / 4 both 0 or -(5/2) with slightly of success my calculations are all best! 19 - Caucasian (American).

Answer 4

The quadratic formula tells you the solution to Ax^2 + Bx + C = 0 in terms of A, B and C:

x = (-B ± √[B² - 4AC])/(2A)

For 2x^+ 8x + 3 = 0, A = 2, B = 8, and C = 3, so

x = (-8 ± √[8² - 4*2*3])/(2*2)
x = (-8 ± √[64 - 24])/4
x = (-8 ± √40)/4

Answer 5

You forgot to divide the 8 by 2 when you simplified the equation. It should be:

x^2 + 4x + 3/2 = 0

or x^2 + 4x = -3/2

Recognizing that 4 is 2 + 2, you can complete the square on the left hand side of the eqn:

x^2 + 4x + 4 = -3/2 +4

(x+2)^2 = 5/2

x+2 = +/-sqrt(5/2)

x = -2 +/- sqrt(5/2)



x

Answer 6

No need to do either of those steps if you are going to use the quadratic formula, which you will need to memorize, but is derived like so:

ax^2 + bx + c = 0; where a,b, and c are constants and a does not equal 0.

x^2 + (b/a)x + c/a = 0
x^2 + (b/a)x = -c/a
x^2 + (b/a)x + (b/2a)^2 = b^2/4a^2 - c/a
(x+b/2a)^2 = (b^2-4ac)/4a^2
x+b/2a = +/- sqrt(b^2-4ac)/2a

x = (-b +- sqrt(b^2 - 4ac))/2a)

Memorized the quadratic formula, and apply it, In this problem a = 2, b = 8, and c = 3.

x=(-8 +- sqrt(64-24))/4
x= -2 +- sqrt(10)/2

Which is about -3.58 and 0.42

Answer 7

Note that x^2+8x+16=(x+4)^2

x^2 + 8x = -3/2

Add both equations by 16
x^2 + 8x + 16 = 29/2

(x+4)^2 = 29/2

Take square root:

x+4 = ± √(29/2)

x = -4 ± √(29/2)

I hope this will help.

Answer 8

You can't solve this:

To solve this you would have to factor 2x² + 8x + 3 but that isn't possible so the value for x doesn't exist.

Answer: DNE (does not exist)

Answer 9

I would gladly show you, step-by-step, if we can find a platform where it is easy to type equations. Give me an e-mail address and I'd send you a step-by-step tutorial.

The trick is to recognize that you dont' even need to rearrange the equation to solve it (find x).