How do you factor #-2x^2 + 1x + 1#?

1 Answer
Nov 7, 2015

Answer:

  • Set the expression = 0 and use the ABC formula
  • Find factors by using #(x - x_1)(x-x_2)#
    #-2x^2 + x + 1 = (x+1/2)(x-1)#

Explanation:

Start by setting the expression equal to zero, then use the ABC-formula.

The ABC-formula is:
#(-b+-sqrt(b^2 - 4ac))/(2a)#

Insert the values for a, b and c (which are the coefficients(red) in your expression: #color(red)(-2)x^2 + color(red)(1)x + color(red)(1)#

#x =(-1 +- sqrt(1^2 - 4 * (-2) * 1)) / (2*(-2)) to (-1 +- sqrt(1+8)) / (-4) to (-1+-3)/-4#

#x_1 = (-1 + 3)/-4= 2/-4 = -1/2#

#x_2 = (-1 - 3)/-4= (-4) /(-4) = 1#

Put these values into #(x-x_1)(x-x_2)#

#(x-(-1/2))(x-1)#
#(x+1/2)(x-1)#