+0

+1
58
2
+300

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

Feb 21, 2021

#1
+939
0

The discriminant needs to be greater than 0.

$$\Delta = b^2- 4ac = 225 - 32c > 0$$

$$c < \frac{225}{32}$$

225/32 is equal to 7.03125, so c can be any integer from 1 to 7. The sum is 28.

Feb 21, 2021
#2
+204
-1

Actually, it's 5040 because the question says product not sum.

Feb 21, 2021