For questions 1-5 estimate the sum or difference.
1. 9/10 + 7/8
a) 1
b)2
c)0
2. 9/50 + 7/15
a)0
b) 1/2
c) 1
3. 2/8/9 - 2/1/7
a) 2
b) 1
c) 0
4. 8/12/31 + 4/5/6
a) 13
b) 12/1/2
c) 14
5. 15/2/15 - 15/1/20
a)2
b) 1
c) 0

Me! 50 points! why does when we come home, our door is unlocked and there is grease on the door knob, me solve this , and i don't know what category this goes under

Ricky takes out a $31,800 student loan to pay his expenses while he is in college. after graduation, he will begin making payments of $190.66 per month for the next 30 years to pay off the loan. how much more will ricky end up paying for the loan than the original value of $31,800? ricky will end up paying $ more than he borrowed to pay off the loan.

Which value of m will create a system of parallel lines with no solution? y = mx - 6 8x - 4y = 12