I have the following homework problem that I do not know how to approach.

Find c such that function defined piecewise is continuous

For what value of the constant c is the function f continuous on ( -∞,∞)f(x) = cx^2 + 2x if x<2

x^3 - cx if x ≥ 2

In the back of the book the answer is suppose to be 2/3. I would like advice on how to approach and solve this problem. Thanks