Question

-3/4 = n - 9/10

Answer 1

First you got to make the denominators of both fractions to match before continuing by finding the LCM. The LCM is 20, so 10 x 2 = 20, so 9 x 2 = 18. So 18/20ths and 4 x 5 = 20, so -3 x 4 = -15. So you have -15/20ths and -18/20ths. Add 18/20ths to both sides to cancel out 18/20ths and then -15 + 18 = 3/20, so n should equal 3/20 or 1.5/10 I suppose. 1.5/10 - 9/10 = -7.5/10 which is also -3/4.
You're answer is n = 3/20ths or 1.5/10ths. I hope that helps!