first you need a common denominator and the would be 20.
-1/10 *2/2= two over twenty (-2/20). 7/4 times by 4 to twenty so 28/20.
-2/20-28/20. Since its already a negative, you just need to add but remember to put the negative sign. So it would be 2/20+28/20=30/20 but add the negative so it would be -30/20. but thats a improper fraction so you need to divide so it would be -1 and 1/2
