I believe 1/9=9, 2/9=18, 3/9=27, 4/9=36
Don't get mad if you get it wrong.
<span>16.1428571 = mean
3.563 = standard deviation
</span>
11, 13, and 16. sorry if im wrong, and i hope this helps.
X+y=-1
3x-y=21
add them equations
x+y=-1
<u>3x-y=21 +</u>
4x+0y=20
4x=20
divide by 4
x=5
x+y=-1
5+y=-1
minus 5 both sides
y=-6
(x,y)
(5,-6)
D is answer