Answer: -(3/10)
Step-by-step explanation:
7/10=r-(-8/9)
(7/10)=r+(8/9)
(7/10)-(8/9)=r
r =(7/10)-(8/9)
r =(7/10)*(9/9)-(8/9)*(10/10) [Multiply each fraction by another fraction equal to one, but with values that will convert the denominator into the same value]
r =(63/90)-(80/90)
r = -(27/90) or -(3/10)
