You had some good answers but here is a more simple approach.
To plot 2x^x-4x+6
In A1:A20 enter numbers (1...20 or 1,1.5,2,...)
In B1 enter =2*A1^2-4*A1+6
Copy this down to B20 by double clicking B1's fill handle (little black
square lower right corner)
Select A1:B20, click Chart Wizard and .........
best wishes