Find the changes in the sign of `4x-5x^(2)+2" for "x in R` and find the extreme value.

Find the changes in the sign of the following expressions and find their extreme values. x^(2)-5x+6

Find the changes in the sign of the following expressions and find their extreme values. 15+4x-3x^(2)

Find the changes of sign of the following expressions and find extreme values i) 15+4x-3x^(2) ii) 4x-5x^(2)+2

Find the sign of 6x^(2)-5x+1 for all real value of x.

Find the sign of 6x^(2)-5x+1 for all real value of x.

Find the value of the polynomial 5x-4x^(2)+3 at. x=2