Which of these systems of equations has a solution of (6,-7)?
A. x-2y=20
2x-y=19
b. x-2y=20
2x+y=19
c. x+2y=20
2x-y=19
d. x+2y=20
2x+y=19

i need more info. are you looked to see there mph? how much they deliver? how far they go?

step-by-step explanation:

yes, gavin is right.

step-by-step explanation:

gavin is correct. 

this problem is about converting 9% per year to how many percent per quarter. the rate is still the same. it only differed in the time period. so, through dimensional analysis,

9% per year  × (1 year / 4 quarters) = 2.25% per quarter

if he was asked to convert 9% per year to how many percent per quarter  compounded quarterly, then you will not simply divide by four. this is because compounding is not linear.

hope this , have a good day. c;

the answer is c. ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀