Answer:
4
Step-by-step explanation:
Plug in the standard deviation formula. This is new to me but it took some research.. Hope it helps
Given:
The system of equations is
...(i)
...(ii)
To find:
The number that must be multiplied with the second equation to eliminate the y-variable.
Solution:
Coefficient of y variable in equation (i) is 3 and in equation (ii) is -1.
To eliminate y-variable the absolute value of coefficients of y-variables should be same.
So, we need to multiply the second equation by 3 to eliminate the y-variable
Multiplying equation (ii) by 3, we get
...(iii)
Adding (i) and (iii), we get


Divide both sides by 7.

Put x=12 in (i).



Divide both sides by 10.

Therefore, x=12 and y=10.
5(8x-2)=270
distribute the 5 into 8x-2
5*8x-5*2=270
you get
40x-10=270
combine like terms
40x=280
divide both sides by 40 to find x
x=7
The answers A and C contain correct information but both of them provide different advice. so the answer is literally your opinion between a and c
The answer is 60
because first you subtract 10 on both sides
then multiply 4 on both sides getting v=60