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

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Answer 1 · 2016-02-29T23:16:49

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

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