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

How do you factor the trinomial 15a^2 - 7a - 515a^2 - 7a - 5?