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

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Answer 1 · 2016-05-21T12:00:57

The solutions for the quadratic equation are:
#color(blue)(x=7#
#color(blue)(x=1#

#y = x^2 -8x + 7#

The equation is of the form #color(blue)(ax^2+bx+c=0# where:
#a=1, b=-8, c=7#

The Discriminant is given by:
#Delta=b^2-4*a*c#

# = (-8)^2-(4 * 1 * 7)#

# = 64 -28 =36#

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

#x = (-(-8)+-sqrt(36))/(2*1) = (8+-6)/2#

#x = ( 8 + 6) /2 = 14/2 = 7#

#x = ( 8 - 6) /2 = 2/2 = 1#