The question, Find two lines that pass through (2 , 8) and are tangent to the curve y=x^3..how do you find slope?..
Since you are asking, I am assuming that you don't fully understand derivatives. The derivative is the slope of the tangent line of a function. Since the slope of any function other than a line is constantly changing, you have to use derivatives to find the slope of the tangent line. To find the slope at that particular point, use the point they gave you (2,8).