Question

For what value of x: -3x^2 + 5x - 12 has maximum value?

Answer 1

1 is your answer because
if we put x=1
-3×1+5×1-12
-3+5-12
-10

Answer 2

given equation is 3x^2+5x-12=0;compare it with normal two degree eqn ax^2+bx+c=0;then a=3;b=5;c=-12
formula:- 4ac-b^2/4a
=4(3)(-12)-(5)^2/4(3)
=-169/12
or
x=-b/2a=-5/2(3)=-5/6