How do you solve #5x^2 + 8x + 7 = 0 # using the quadratic formula?

1 Answer
Oct 21, 2015

Answer:

The solutions are
#x=color(blue)((-8+sqrt(-76))/10#
#x=color(blue)((-8-sqrt(-76))/10#

Explanation:

#5x^2+8x+7=0#

The equation is of the form #color(blue)(ax^2+bx+c=0# where:
#a=5, b=8, c=7#

The Discriminant is given by:

#Delta=b^2-4*a*c#

# = (8)^2-(4*5*7)#

# = 64- 140= -76#

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

#x = (-(8)+-sqrt(-76))/(2*5) = (-8+-sqrt(-76))/10#

The solutions are
#x=color(blue)((-8+sqrt(-76))/10#
#x=color(blue)((-8-sqrt(-76))/10#