How do you solve # 7x^2+2x-2=0# using the quadratic formula?

1 Answer
Oct 19, 2015

Answer:

#x= (-1+-sqrt(15))/7#

Explanation:

Given a quadratic equationin the form:
#color(white)("XXX")color(red)(a)x^2+color(blue)(b)x+color(green)(c) = 0#
the quadratic formula tells us that the solutions are:
#color(white)("XXX")x= (-color(blue)(b)+-sqrt(color(blue)(b)^2-4color(red)(a)color(green)(c)))/(2color(red)(a))#

Given
#color(white)("XXX")color(red)(7)x^2+color(blue)(2)x+color(green)(-2)#
this becomes
#color(white)("XXX")x= (-color(blue)(2)+-sqrt(color(blue)(2)^2-4 * color(red)(7) * color(green)((-2))))/(2 * color(red)(7))#

#color(white)("XXXXX")= (-1+-sqrt(15))/7#