Goto Line and scrolling in RichTextBox

Hi, does anybody know how to go to a particular line in a RichTextBox?

I am writing a program where I have 2 rich text box side by side. The 2 text box have similar number of lines, though content is different. First text box is for user to type, whereas 2nd text box is for program to give comments. I want to control it such that whenever user scroll down from first text box, the 2nd text box will scroll as well (synchronized scrolling). In addition, the 2nd RichTextBox should not allow user to type or scroll (can I disable the scroll bar or should I use some other control other than RichTextBox).