0
|2r + 9| = 5
So 2r + 9 = 5 or 2r + 9 = -5
so that 2r = -4 or 2r = -14
r = -2 or r = -7
12-2r = 10
4r2-25 = (2r)2-52 = (2r-5)(2r+5)
2r-1=9 2r =10 r =5
11