Use your number line to glean the relevant information. On the number line, the values at which "x" exists should be clearly marked. If x is greater than 4, for instance, there will be a bold line starting at x = 4 and extending to the right, via arrow, into infinity. If "x" is between -2 and 4, there should be a dark line connecting -2 and 4 on the number line. If the endpoints of "x" are included in the inequality, they will be marked by dark circles; if they are not included, there will be bubbles over the endpoints.
Access the "Y=" part of your graphing calculator. Enter your inequality into "Y1" and/or "Y2." For example, suppose "x" is be between -2 and 4, inclusive. This indicates that x >= -2 and x <= 4. In Y1, type in x >= -2. In Y2, type in x <= 4.
Hit "Graph" to access a graph of your function. Your calculator will provide a straight line, ranging from x = -2 to x = 4.