Question #5fd61

1 Answer
Nghi N.
Feb 6, 2017

y-intercept = 8
x-intercepts:
#x = (7 +- sqrt17)/2#

Explanation:

#f(x) = x^2 - 7x + 8 #
To find y-intercept, make x = 0
x = 0 --> y-intercept --> f(0) = 8
To find x-intercepts, make y = 0, and solve this quadratic equation by using the improved quadratic formula (Socratic Search):
#x^2 - 7x + 8 = 0#
#D = d^2 = b^2 - 4ac = 49 - 32 = 17# --> # d = +- sqrt17#
There are 2 real roots (two x- intercepts):
#x = -b/(2a) +- d/(2a) = 7/2 +- sqrt17/2 = (7 +- sqrt17)/2#

Related questions
See all questions in Intercepts by Substitution
Impact of this question
1121 views around the world
You can reuse this answer
Creative Commons License