How do you solve 3x (x - 2) = 1?

1 Answer
Aug 19, 2015

The solutions are
color(blue)(x=(3+2sqrt3)/3
color(blue)(x=(3-2sqrt3)/3

Explanation:

3x(x−2)=1

3x^2−6x=1

3x^2−6x-1=0

The equation is of the form color(blue)(ax^2+bx+c=0 where:
a=3, b=-6, c=-1

The Discriminant is given by:
Delta=b^2-4*a*c

= (-6)^2-(4*3*(-1))

= 36+12=48

The solutions are found using the formula
x=(-b+-sqrtDelta)/(2*a)

x = (-(-6)+-sqrt(48))/(2*3) = (6+-4sqrt(3))/6

( cancel2(3+-2sqrt(3)))/cancel6 = (3+-2sqrt3)/3

The solutions are
color(blue)(x=(3+2sqrt3)/3
color(blue)(x=(3-2sqrt3)/3