use the quadratic formula to solve the equation 2x^2+1=6x

Question

 Use the  quadratic formula to solve the equation 2x ^ 2 + 1 = 6x Im not sure if the answer is 4,-3/2 I worked it out but they keep saying its wrong whats missing

Answer 1

2x² + 1 = 6x

 

First, put this in standard form:  2x² - 6x + 1 = 0

 

Using a = 2, b = -6, and c = 1, the quadratic formula gives: x = (6 ±√(36 - 4(2)(1)))/4

 

So x = (6 ± √(36 - 8)/3 = (6 ± √28)/4 = (6 ± 2√7)/4 = (3 ± √7)/2

 

 

Answer 2

Hey there.

Rearrange to have everything on the left hand side:

2x² -6x+1 = 0

a = 2

b = -6

c = 1

 

Using the quadratic formula:

x_1,2 = [-b± √(b² - 4ac)]/2a = [6± √(36 - 4*2*1)]/2*2 = [6± √(36 - 8)]/4 = [6± √(28)]/4 = (6± 2√7) / 4 = (3±√7)/2

For numerical solutions:

x₁ = (6 + 5.29) / 4 = 2.82

x₂ = (6 - 5.29) / 4 = 0.18

 

Cheers,

Rubi Pinchasov