14. 1.5, 10 <- Answer
15. 5,1 <- Answer
Proof 14
Solve the following system:
{2 x - y = -7 | (equation 1)
4 x - y = -4 | (equation 2)
Swap equation 1 with equation 2:
{4 x - y = -4 | (equation 1)
2 x - y = -7 | (equation 2)
Subtract 1/2 × (equation 1) from equation 2:
{4 x - y = -4 | (equation 1)
0 x - y/2 = -5 | (equation 2)
Multiply equation 2 by -2:
{4 x - y = -4 | (equation 1)
0 x+y = 10 | (equation 2)
Add equation 2 to equation 1:
{4 x+0 y = 6 | (equation 1)
0 x+y = 10 | (equation 2)
Divide equation 1 by 4:
{x+0 y = 3/2 | (equation 1)
0 x+y = 10 | (equation 2)
Collect results:
Answer: {x = 1.5
y = 10
Proof 15.
Solve the following system:
{5 x + 7 y = 32 | (equation 1)
8 x + 6 y = 46 | (equation 2)
Swap equation 1 with equation 2:
{8 x + 6 y = 46 | (equation 1)
5 x + 7 y = 32 | (equation 2)
Subtract 5/8 × (equation 1) from equation 2:{8 x + 6 y = 46 | (equation 1)
0 x+(13 y)/4 = 13/4 | (equation 2)
Divide equation 1 by 2:
{4 x + 3 y = 23 | (equation 1)
0 x+(13 y)/4 = 13/4 | (equation 2)
Multiply equation 2 by 4/13:
{4 x + 3 y = 23 | (equation 1)
0 x+y = 1 | (equation 2)
Subtract 3 × (equation 2) from equation 1:
{4 x+0 y = 20 | (equation 1)
0 x+y = 1 | (equation 2)
Divide equation 1 by 4:
{x+0 y = 5 | (equation 1)
0 x+y = 1 | (equation 2)
Collect results:
Answer: {x = 5 y = 1
The first set of parentheses is unnecessary, so just drop it.
The second set of parentheses has a negative sign to its left.
To simplify the second set of parentheses, change every sign inside the parentheses. Then combine like terms.
<span>(–x – 2) – (4x + 3) =
= - x - 2 - 4x - 3
= -x - 4x - 2 - 3
= -5x - 5
</span>
You are wrong.
1, 2, 3 and 4 are correct.
5. 75%
6 is also correct
7. 100%
8. 50%
Answer:
3. mean of 2nd is larger
Step-by-step explanation:
mean of 2nd sem 87 > 86.8 1st sem
<h2>
Hello!</h2>
The answer is: George made his first mistake in Step 1.
<h2>
Why?</h2>
Getting a result of 26 cars needed means that he didn't take in consideration the next month in the mean calculation.
We have information of the number of sold cars of the first seven months, but if he wants to calculate the number of cards he needs to have a mean of 24 sold cards next months, he should take in consideration an extra month (the eighth month).
Checking the mistake:
So, it proves that he made a mistake by multiplying it into 7 and instead into 8
The correct answer would be:
He needed to include the eighth month in order to calculate how many cars he should sell next months in order to have a mean of 24 cars.
Have a nice day!
