How do you use the quadratic formula to solve for x-intercepts #x^2 - 8x + 12 = 0#?

1 Answer
Aug 7, 2017

Answer:

See a solution process below:

Explanation:

The quadratic formula states:

For #color(red)(a)x^2 + color(blue)(b)x + color(green)(c) = 0#, the values of #x# which are the solutions to the equation are given by:

#x = (-color(blue)(b) +- sqrt(color(blue)(b)^2 - (4color(red)(a)color(green)(c))))/(2 * color(red)(a))#

Substituting:

#color(red)(1)# for #color(red)(a)#

#color(blue)(-8)# for #color(blue)(b)#

#color(green)(12)# for #color(green)(c)# gives:

#x = (-color(blue)((-8)) +- sqrt(color(blue)((-8))^2 - (4 * color(red)(1) * color(green)(12))))/(2 * color(red)(1))#

#x = (color(blue)(8) +- sqrt(color(blue)(64) - 48))/2#

#x = (color(blue)(8) +- sqrt(16))/2#

#x = (color(blue)(8) - 4)/2# and #x = (color(blue)(8) + 4)/2#

#x = 4/2# and #x = 12/2#

#x = 2# and #x = 6#