How do you solve #3x^2 - 10 = 2x# by completing the square?

1 Answer
May 10, 2016
  1. Move the constant to the right
  2. Make a = 1
  3. Add on #(b/2)^2# to both sides
  4. Write as (x +- b/2)^2 =
  5. Find square toot of both sides
  6. Solve twice - pos and neg square root

#3x^2 - 10 = 2x rArr 3x^2 - 2x = 10#

#x^2 - (2x)/3 + color(red)((1/3)^2) = 10/3 + color(red)((1/3)^2)#
#(x - 1/3)^2 = 31/9#

#x - 1/3 = +-sqrt31/3#

# x = sqrt31/3 + 1/3 " or " x = -sqrt31/3 + 1/3#

#x = 2.189 or x = -1.523#