Question #2c02b

1 Answer
Tamir E.
Nov 19, 2017

#x_1=1 2/3~~1.667#
#x_2=1/5=0.2#

Explanation:

#ax^2+bx+c=0#
#x_(1,2)=(-b+-sqrt(b^2-4*a*c))/(2*a)#

#15x^2-28x+5=0#
#=>#
#a=15#
#b=-28#
#c=5#
#=>#
#x_(1,2)=(-(-28)+-sqrt((-28)^2-4*(15)*(5)))/(2*(15))=#
#=(28+-sqrt(784-300))/(30)=#
#=(28+-sqrt(484))/(30)=#
#=(28+-22)/(30)=#
#=>#
#x_1=(28+22)/(30)=50/30=5/3=1 2/3~~1.667#
#x_2=(28-22)/(30)=6/30=2/10=1/5=0.2#

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