SOLUTION: Find the zeroes of the function algebraically f(x) =2x2-3x-20

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Question 1031481: Find the zeroes of the function algebraically f(x) =2x2-3x-20
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Try to factorize the function if possible; or look at discriminant:

%28-3%29%5E2-4%2A2%2A%28-20%29
9%2B8%2A20
9%2B160
169
13%5E2

If you use general solution for quadratic expression,
zeros are %283%2B-+13%29%2F4
-10%2F4=highlight%28-5%2F2%29
or
16%2F4=highlight%284%29
The two zeros.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Find the zeroes of the function algebraically f(x) =2x2-3x-20
2x%5E2+-+3x-+20

(2x + 5)(x - 4) = 0

2x + 5 = 0      OR      x - 4 = 0

2x = - 5        OR      x = 0 + 4 

highlight_green%28matrix%281%2C3%2C+x+=+-%285%2F2%29%2C+or%2C+x+=+4%29%29