Simplify and decide which is greater: 6r-1+6r+1*(11) or r+11 + 8r + 2 + 29?

First you want to add spaces in a consistent manner so the presentation is easy to read.

6r - 1 + 6r + 1*(11) The term 1*(11) is equivalent to fluttering cards in your face. It only means 11. The statement adds up to 12r + 10.

r + 11+ 8r + 2 + 29 This is not "simplify", this is "evaluate". It adds up to 9r + 42.

Now it looks like 12r + 10 would be greater that 9r + 2, but not always. Let's make them equal and see what happens.

12r + 10 = 9r + 42 The rule is you can do any valid operation on both sides of an equation and it will still be equal. Subtract 9r.

3r + 10 = 42 Subtract 10.

3r = 32 Divide by 3.

r = 10 2/3 This says the two statements are equal at r = 10 2/3. For values of r less than that, 9r + 42 is greater, and for values of r greater than that, 12r + 10 is greater.

If you rewrite this as y = 9x + 42, y = 12x + 10 you can plot the two lines. It looks like this:
www.wolframalpha.com/input/?i=plot+y+%3D+9x+%2B+42,+y+%3D+12x+%2B+10