C1 Maths differentiaiton

Use the quadratic formula?

Complete the square

Is it not: 6x^2 - 10x - 4 = 0 (have to subtract the thirteen)

That becomes 3x^2 - 5x - 2 = 0 (dividing by 2)

This can be factorised.

:O maybe although im bad at factosriisng it takes me ages =/

I did intally but doing all those surds and things without a claultor makes it very difficult =/

x = 2 and x = -1/3, the x values you got are wrong!

Opp ye it should be (3x +1) (x -2) I understand why x = 2 but not 1/3 woudnt it just be -1 beucase you swap the sign of the +1 ?

3x+1 = 0
3x = -1
x = -1/3

If you didn't understand that, don't be shy to post here

Ah right ye that makes sense and then i just plug those 2 values in to get Y?

They alos get an asnwer of (2,13)...

Find the two points on the curve Y=2x^3 - 5x^2 +9x -1 where the gradient = 13.

So i differentaited to get 6x^2 -10x +9 I then set that equal to the gradient so 6x^2 -10x +9 =13. Then I turned it into a quadratic by subtracting to get 6x^2 -10x +9 =0 and was going to solve for x that way but its a non calculatro question and the asnweres in thebook are given as a fraction, ut i cant see how to factorise this anyone help?