Solve the system by substitution -x-y-z=-8 -4x+4y+5z=7 2x+2z=4

Solve the first equation for x.

x + 3y = -7

x = -7 - 3y

Now substitute (-7 - 3y) in for x in the second equation.

2x + 4y = -4

2(-7 - 3y) + 4y  = -4

Solve to find the value of y.

-14 - 6y + 4y = -4

-14 - 2y = -4

-2y = 10

y = -5

9 is your mean

Step-by-step explanation:

1. Add them all up.

2. Divide by the number of numbers there is.

3. That is your mean.

1) 7+21+2+17+3+13+7+4+9+7+9=99.

2) divide by 11 99/11 = 9

3) 9 is our mean.

Hope this helps plz hit the crown :D