How do you find all zeros of the function $f(x)=3x^2-17x+20$ ?

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Answer 1 · 2016-03-12T00:11:20

$x = 4$ or $x = 5/3$

$3x^2-17x+20$ is of the form $ax^2+bx+c$ with $a=3$ , $b=-17$ and $c=20$ .

This has zeros given by the quadratic formula:

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

$=(17+-sqrt((-17)^2-(4*3*20)))/(2*3)$

$=(17+-sqrt(289-240))/6$

$=(17+-sqrt(49))/6$

$=(17+-7)/6$

That is $x = 4$ or $x = 5/3$

How do you find all zeros of the function f(x)=3x^2-17x+20f(x)=3x^2-17x+20?