<span>expressions for the mean and standard deviation of y if this variable is determined by the expression y
</span>
![\left[\begin{array}{ccc}1&2&3\\4&5&6\\7&8&9\end{array}\right]](https://tex.z-dn.net/?f=%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%262%263%5C%5C4%265%266%5C%5C7%268%269%5Cend%7Barray%7D%5Cright%5D%20)
So first, you have to get two of the same variables to cancel out. Let's do this for x. In order for the x's to cancel out, we could multiply the bottom problem by 2.
(2) 3x-6y=24
After multiplying all the numbers by 2, you get the equation 6x-12y=48
The set of equations is now
-6x+2y=12
6x-12y=48
Now you can add them. The x variables cancel out, so you are left with the y variable.
2y+-12y=-10y and 12+48=60
Then you would divide 60 by -10 to get y=-6.
You would plug the answer for y into one of the original equations, lets do the top one. -6x+2y=12 becomes -6x+2(-6)=12
You'd multiply the 2 and -6 to get -12 so the equation is
-6x-12=12
The negative 12 turn positive and you add to both sides to get the -6x alone.
-6x-12=12
+12=12
-6x=24
Then divide 24 by -6
X=4
(-4,-6) is your final answer.
I'll help you with #7, and hopefully then you will be able to do #8 on your own. the formula for the volume of a pyramid and cone is the area of the base times the height of the figure divided by three. knowing this, we must first find the area of the base. since it is a square, we need to multiply the length times the width. (6 • 6 = 36) then you multiply that times the height of the figure (36 • 4 = 144) finally, we need to divide that by three (144 divide by three is 48.) so the answer is b. hope this helped :$
Answer:
No 1
Here,
Let X be age of daughter
and 3X be age of father
Now,x+17+3 = 20 age
and 3x+43-20 = 7point9x
Step-by-step explanation:
So,
20÷7point9 = 2point8 years ago
Hence,
age of father = 48÷2point8 = 21point5 years
age of daughter = 20÷2point8 = 10 years
so, before 2point8 years ago father was as old as his daughter
Answer:
triangle square hexagon, triangle square hexagon
