Your graphical calculator is your best friend. Never leave home without it, providing you're going to a class or an exam.
Using graphs we can work out intercepts; solve simulatneous equations and help you out with lots of statistical nightmares.
First of all you want to go into 'graph' or 5 from the main menu, clicking exit will take you a page where you can input functions. Let's say were tying to work out the y-intercept of y=x2+7. Input using key board not the function keys and then click 'draw' or F6. At this point you may not see anything more than a pair of axis. In reality this doesnt matter too much, but you should be able to zoom out (F2, F4 then EXE). To find the y-intercept click G-Solv (F5) and choose Y-Int or F4. But bear in mind, if this is an exam question you'll need to be able to write down how to transform y=x2+7 into y=7 when x=0 !