Find the range of values of m for which the function 3x^2 -12x + m is negative for all values of x.
Is it possible for the function to be negative ? If so, how ?I tried using b^2 - 4ac < 0 and the result is m > 12 . However when i tried substituting *13* as the value of m and *1* as the value of x, the result is a positive number.
The rules are this way :
ax˛+bx+c
If the discriminant is strictly negative
The trinomial is of the same sign as a.
If the discriminant is equal to 0
Then it's a multiple of a perfect square and the sign is the sign of a.
If the discriminant is positive
There are 2 real roots and
And the sign of the trinomial is as following :
- sign of a in
- inverse sign of a in