What is the solution of the system for 1-3?

1. Y=x+6
Y=2

A. (6,12)
B. (-12,-6)
C. (-6,-12)
D. 2,4

2. 3x+2y=7
-3x+11=y

A. (6,-3)
B. (6,-7)
C. [-4,19/2}
D. (5,-4)

3. 2x-y=7
4x-y=-4

A. (-1.5,4)
B. (1.5,10)
C. 4,1.5)
D. 1.5,-2)

For part one, round the number of seconds in a year, to an easy number, depending on how many significant figure then divide that by 3600, the number of seconds in an hour to get the number of hours in a year. for part 2 do the same but use the exact number instead of the rounded, scientific notation is expressed by using a number between 1 and 10 multiplied by a power of 10 which is how many digits to the left (positive exponent) or right (negative exponent) you must move to get a number from 1 to 10
for part three just explain what is the same or different about your 2 answers.