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

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Answer 1 · 2015-10-21T04:45:23

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

#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#