How do you factor the trinomial #15a^2 - 7a - 5#?

1 Answer
Feb 29, 2016

#color(blue)(x~=0.856" ; "x ~=-0.389" "" to 3 decimal places")#

Explanation:

This has non integer roots so you need to use the formula

Standard form

#" "ax^2-bx+c=0#

#x=(-b+-sqrt(b^2-4ac))/(2a)#

Where:
#a=15#
#b=-7#
#c=-5#
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#x=(+7+-sqrt((-7)^2-4(15)(-5)))/(2(15)#

#x=(7+-sqrt(49+300))/(2(15))#

#color(blue)(x~=0.856" ; "x ~=-0.389" "" to 3 decimal places")#

Tony B