Whats the answer to -2x² +8x + 3 = 1 using the Quadratic formula?

Question

i just tried to solve it myself but when i tried to check it i noticed that i did somethin wrong. shows steps please.

quadratic formula:

-b +or - √b² - 4ac / 2a

these too plz:

1. 2y² - 8y + 5 = 0

2. 3x² - 5x = -1

3. 3x² +2 = -8x

Answer 1

OK

First get it to = 0.

-2x^2 + 8x +2 = 0

-8 +- sqrt(64 - (4)(-2)(2) / 2(-2)

-8 +- sqrt(64+16) / -4

-8 +- sqrt(80) / -4

-8 +-4sqrt(5) / -4

2+-sqrt(5)

I'll let yo do the others.

Hope that helps.  

Answer 2

-2x² +8x + 3 = 1

-2x² +8x + 2 = 0

64 -(4.(-2).2)= 80

(-8+-√80)/-4

x'=(-8+4√5)/-4 = (4(-2+√5))/-4 = 2-√5

x"=(-8-4√5)/-4 = (-4(2+√5))/-4 = 2+√5

1. 2y² - 8y + 5 = 0

64-40=24

(8+-√24)/4= (8+-2√6)/4

x'=(8+2√6)/4= (2(4+√6))/4 = (4+√6)/2

x"=(8-2√6)/4= (2(4-√6))/4 = (4-√6)/2

2. 3x² - 5x = -1

   3x² - 5x + 1= 0

25-12=13

(5+-√13)/6

x'=(5+√13)/6

x"=(5-√13)/6

3. 3x² +2 = -8x

   3x² +8x+2 = 0

64-24 = 40

(-8+-√40)/6 = (-8+-2√10)/6 = (2(-4+-√10))/6  

x'=(2(-4+√10))/6=(-4+√10)/3    

x"=(2(-4-√10))/6=(-4-√10)/3

I hope it's all right!

Answer 3

The equation has to be set to zero

-2x² + 8x + 2 = 0

Use the quadratic formula to solve

   ax²+bx+c=0

where

   a=-2

   b=8

   c=2

x = [-b ± √(b²-4ac)] / (2a)

   = [-(8) ± √((8)² - 4(-2)(2))] / 2(-2)

   = [-8 ± √(80)] / -4

   = [-8 ± √(2⁴)√(5)] / -4

   = [-8 ± 4√5] / -4

   = 2 ± -2.236

x₁ = 2 + -2.236 = -0.236

x₂ = 2 - -2.236 = 4.236

Answer 4

16.94 and -9.44, 12.90 and 3.10, -2.09 and -12.91, 21.49 and 2.51

No guarantees on those, but they should be right.