How do you solve -x-y-3z=-9 z=3x-1 x-5y+z=21 using elimination

Assuming these are three separate problems, I have solved them for you below.

1.)

Multiply the whole thing by -1 so x is positive.

2.)

⇒

⇒

Isolate x⇒

⇒

3.)

⇒

⇒

⇒

answer: expected value of x = 1.0

step-by-step explanation:

p(x=0) = 0.25

p(x=1) = 0.50

p(x=2) = 0.25

expected value for x = 0×0.25 + 1×0.5 + 2×0.25 = 1.0

where is the figure