ANSWER
The solution is
x=-3,y=-2
EXPLANATION
First equation
3x – 3y = –3
Second Equation:
5x – y = –13
Multiply the second equation by 3 to get:
Third equation:
15x-3y=-39
Subtract the first equation from the third equation:


Divide both sides by 12,

Put x=-3 into the first equation:


Group like terms,



The solution is
x=-3,y=-2
Answer:
2/14, 4/28, 5/35, 7/70 or just 2/14
Step-by-step explanation:
Multiply both the numerator and denominator of 1/7 by 2, to get 2/14, or 2:14
And multiply the numerator and denominator of 1/7 by 3, to get 3/21, or 3:21. So 2:14 and 3:21 are two ratios that are equal to 1:7.
Answer:
As both the mean and standard deviation are in the desired ranges, the tool passes the technical control.
Step-by-step explanation:
Mean of the batch:
The mean of the batch is the sum of all values divided by the number of items. So

Mean in the desired interval.
Standard deviation:
Square root of the sum of the difference squared between each term and the mean, divided by the number of items. So

As both the mean and standard deviation are in the desired ranges, the tool passes the technical control.
920,438. 921,438-1,000=920,438