15. -(-7y + 12) = 7y - 12
16. 1/a = 16/18
cross multiply
16a = 18
a = 18/16 = 9/8
17. 8x - 12 = 4x + 24
8x - 4x = 24 + 12
4x = 36
x = 36/4
x = 9
18. -6b > 42 4b > -4
b < 42/-6 b > -4/4
b < - 7 b > -1
so b < -7 and b > -1
19. 6 more then the product of 8 and n
6 + 8n
20. 45 = 3b + 69
45 - 69 = 3b
-24 = 3b
-24/3 = b
-8 = b
Answer:
Jessica had 32 candies at the beginning.
Step-by-step explanation:
Let the number of candies Jessica had at the beginning be 
.
Candies gives to Judy = 
.
Now, candies left with Jessica is 
.
Candies given to Reggie is 
of 
.
∴ Candies with Reggie is 
.
Candies left with Jessica after giving to Reggie = 
.
Now, Jessica lost 75% of what she had left. So, 75% of 
.
∴ Candies lost = 
Now, candies left with Jessica = 
.
As per question,
Candies left with Jessica at last is 4. So,
Hence, Jessica had 32 candies at the beginning.
Answer:
x = -1
, y = 5
Step-by-step explanation:
Solve the following system:
{5 x + 3 y = 10 | (equation 1)
x = y - 6 | (equation 2)
Express the system in standard form:
{5 x + 3 y = 10 | (equation 1)
x - y = -6 | (equation 2)
Subtract 1/5 × (equation 1) from equation 2:
{5 x + 3 y = 10 | (equation 1)
0 x - (8 y)/5 = -8 | (equation 2)
Multiply equation 2 by -5/8:
{5 x + 3 y = 10 | (equation 1)
0 x+y = 5 | (equation 2)
Subtract 3 × (equation 2) from equation 1:
{5 x+0 y = -5 | (equation 1)
0 x+y = 5 | (equation 2)
Divide equation 1 by 5:
{x+0 y = -1 | (equation 1)
0 x+y = 5 | (equation 2)
Collect results:
Answer: {x = -1
, y = 5
The fraction of the variability in fuel economy is accounted for by the engine size is 59.91%.
Given that, r= -0.774.
To solve such problems we must know about the fraction of the variability in data values or R-squared.
<h3>What fraction of the variability in fuel economy is accounted for by the engine size?</h3>
The fraction by which the variance of the dependent variable is greater than the variance of the errors is known as R-squared.
It is called so because it is the square of the correlation between the dependent and independent variables, which is commonly denoted by “r” in a simple regression model.
Fraction of the variability in data values = (coefficient of correlation)²= r²
Now, the variability in fuel economy = r²= (-0.774)²
= 0.599076%= 59.91%
Hence, the fraction of the variability in fuel economy accounted for by the engine size is 59.91%.
To learn more about the fraction of the variability visit:
brainly.com/question/2516132.
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