Sure,
-2 1/4=r-4/5
1. Convert 2 1/4 to improper fraction. Use this rule_ a b/c = (ac+b)/c
-(2*4+1)/4=r-4/5
2. Simplify 2*4 to 8
-(8+1)/4=r-4/5
3. Simplify 8+1 to 9
-9/4=r-4/5
4. Add 4/5 to both sides
-9/4+4/5=r
5. Simplify -9/4+4/5 to -29/5
-(9*5)/(4*5) + (4*4)/(5*4)
-45/20 + 16/20
(-45+16)/20
-29/20
r=-29/20
r=-1.45
Have a nice day :D