Question

The value of the discriminant of 2x^2 + bx + 3 is greater than zero. What is the value of b?

A. 4
B. 5
C. 6
D. Cannot be determined

Also, we are learning how to choose "Cannot be determined" properly. So make sure 100% that you can't solve it, before answering cannot be determined! Thanks

Answer 1

what part of the quadratic formula relates to the discriminant?

Answer 2

all of them.. doesn't it? because you have (b)^2 -4 (a)(c)?

Answer 3

b^2 - 4ac > 0

b^2 > 4(3)(2)

b^2 > 24

Answer 4

Obviously, B and C are correct

Answer 5

im not sure what is meant by "cannot be determined" because a range of possibilities can definantly be determined

Answer 6

hmm.. that is what I thought... which one is the best option?

Answer 7

can there only be one choice?

Answer 8

yes.. only one choice

Answer 9

the question is broke lol, go with d and hit next

Answer 10

hmm, @apoorvk what do you think?

Answer 11

if there were infinite number of answers.. could cannot be determined work?

Answer 12

for a quadratic of the standard form "ax^2+bx+c=0", the discriminant D=b^2-4ac.
comparing coefficients with your equation,
'a' = 2
'b' = b
'c' = 3
It says D>0
so,
b^2 - 4x2x3 > 0
or,
b^2 > 24
or,
b< -(sqrt24) AND b > sqrt(24)

sqrt of 24, now, is ---> 2sqrt 6 = approx. 4.9

so,

b>4.9
and
b<-4.9


so, both '5' and '6' satisfy the constraint - hence 'B' and 'C' both are correct!



From the options given to you,

Answer 13

so, as amistre says, if according to the instructions only one option may be correct - the question is broke.

Answer 14

Hah, the question must be broke! I'll make a note the concern on my paper.. saying both b and c are possible answers. It works, right? (: I have one more question for tonight