Question

Find the maximum or minimum value:

-x^2+2x+5

3x^2-4x-2

can someone explain these to me step by step

Answer 1

you could use a TI-83 plus graphing calculator...if that helps

Answer 2

also if the coefficient is negative then it has a minimum value and if it's a positive thenn it has a maximum vlaue

Answer 3

You are probably using "completing the square"

I will do the second one, follow the same procedure to do the first

3x^2-4x-2
= 3[x^2 - (4/3)x + 4/9 - 4/9] - 2
= 3[(x-2/3)^2 - 4/9] - 2
= 3(x-2/3^2 - 4/3 - 6/3
= 3(x-2/3)^2 - 10/3

The minimum value is 10/3 when x = 2/3