Y=20x -1500, y equals the prophet, x is the number of books, 20 is the money made after taking out the cost of production, 1500 is a cost that only occurs once.
X^2 + 5x = -2
x^2 + 5x + 2 = 0
x = -b (+-) sqrt (b^2 - 4ac) / 2a
a = 1, b = 5, and c = 2
x = -5 (+-) sqrt (5^2 - 4(1)(2)) / 2(1)
x = -5 (+-) sqrt (25 - 8) / 2
x = -5 (+-) sqrt (17) / 2
answer is : negative 5 plus or minus the square root of 17 divided by 2
3(2x^2 + 4) - 4(x - 6)
= 6x^2 + 12 - 4x + 24
= 6x^2 - 4x + 36
therefore first answer is correct
Answer:
The null and alternative hypotheses are:


Under the null hypothesis, the test statistic is:

Where:
is the sample mean
is the sample standard deviation
is the sample size

Now, the right tailed t critical value at 0.05 significance level for df = n-1 = 10-1 = 9 is:

Since the t statistic is less than the t critical value at 0.05 significance level, therefore,we fail to reject the null hypothesis and conclude that there is not sufficient evidence to support the claim that the average phone bill has increased.
Y = 1.3x
point C : (3,?)...so we sub in 3 for x and solve for y
y = 1.3(3)
y = 3.9
so point C is (3,3.9)
point D : (-6,?)...so we sub in -6 for x and solve for y
y = 1.3(-6)
y = -7.8
so point D is (-6,-7.8)