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Find the product of all positive integer values of c such that 8x^2+15x+c=0 has two real roots.

 

HELp

 Oct 4, 2019
 #1
avatar+104962 
+2

8x^2 + 15x + c  = 0

 

Using  the discriminant  we will have two real roots when

 

15^2  - 4*8*C  >  0

 

225  - 32C  > 0

 

225 > 32C

 

225/32 > C

 

C <  225/32

 

C < ≈ 7.03

 

So....  

 

1 ≤ C ≤ 7 

 

So the product of the possible C's   =  7!   =   5040

 

 

cool cool cool

 Oct 4, 2019
edited by CPhill  Oct 4, 2019

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