−2x + 3y + 5z = −21
−4z = 20
6x − 3y = 0
do -4z=20 first
divide both sides by -4 to get z by itself
-4z/-4=20/-4
z=-5
Use z=-5 into −2x + 3y + 5z = −21
-2x+3y+5(-5)=-21
-2x+3y-25=-21
move -25 to the other side
sign changes from -25 to +25
-2x+3y-25+25=-21+25
-2x+3y=4
6x-3y=0
find x by eliminating y
Add the equations together
-2x+6x+3y+(-3y)=4+0
-2x+6x+3y-3y=4
4x=4
Divide by 4 for both sides
4x/4=4/4
x=1
Use x=1 into 6x − 3y = 0
6(1)-3y=0
6-3y=0
Move 6 to the other side
6-6-3y=0-6
-3y=-6
Divide both sides by -3
-3y/-3=-6/-3
y=2
Answer:
(1, 2, -5)
Answer: 3.14285714.....
<u>Step-by-step explanation:</u>
pi is 

Thiis is a non-terminating and non-repeating decimal.
To solve for s all you have to do is factor the 7 and simplify the rest.
7s-21=21
7s=42
s=6
Answer:
D
Step-by-step explanation:
Answer:


Step-by-step explanation:
From the question we are told that:
Sample size n=9
Number of Green 
Number of yellow 
Number of white 
Probability of Green Followed by yellow P(GY) ball


Generally the equations for when n is even is mathematically given by



Therefore



Generally the equations for when n is odd is mathematically given by



b)
Probability of drawing white ball

Therefore



Therefore
![E(y)=[E(w)-1]\frac{4}{9}](https://tex.z-dn.net/?f=E%28y%29%3D%5BE%28w%29-1%5D%5Cfrac%7B4%7D%7B9%7D)
![E(y)=[\frac{9}{2}-1]\frac{4}{9}](https://tex.z-dn.net/?f=E%28y%29%3D%5B%5Cfrac%7B9%7D%7B2%7D-1%5D%5Cfrac%7B4%7D%7B9%7D)
