Looks like you have typo in your equation/expression:

If you need to calculate the expression '3x^2−3x+9' for 'x = -2' you need to plug in 'x = -2' into '3x^2−3x+9':

3*(-2)^2-3*(-2)+9

This way you will get the result:

3*(-2)^2-3*(-2)+9 = 27

Click here to see the calculation