What are the exact solutions of #x^2=4-7x#?

1 Answer
Nghi N
Jul 1, 2017

#x = (-7 +- sqrt65)/2#

Explanation:

#y = x^2 + 7x - 4 = 0#
Use the improves quadratic formula (Socratic Search):
#D = d^2 = b^2 - 4ac = 49 + 16 = 65# --> #d = +- sqrt65#
There are 2 real roots:
#x = -b/(2a) +- d/(2a) = - 7/2 +- sqrt65/2 = (-7 +- sqrt65)/2#

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