Answer:
See below ~
Step-by-step explanation:
<u>Question 1</u>
⇒ -7x - (8x + 16) = -1
⇒ -7x - 8x - 16 = -1
⇒ -15x = 15
⇒ x = -1
⇒ y = 8(-1) + 16 = 8
⇒ Solution = <u>(-1, 8)</u>
<u></u>
<u>Question 2</u>
⇒ 3x + 4(-3x - 18) = 0
⇒ 3x - 12x - 72 = 0
⇒ -9x = 72
⇒ x = -8
⇒ y = -3(-8) - 18 = 6
⇒ Solution = <u>(-8, 6)</u>
<u>Question 3</u> (not clear)
<u>Question 4</u>
⇒ -8x - 7(6x) = 0
⇒ -8x - 42x = 0
⇒ -50x = 0
⇒ x = 0
⇒ y = 6(0) = 0
⇒ Solution = <u>(0, 0)</u>
<u>Question 8</u>
- 2x - 6y = -14
- y = -5x - 19
⇒ 2x - 6(-5x - 19) = -14
⇒ 2x + 30x + 114 = -14
⇒ 32x = -128
⇒ x = -4
⇒ y = -5(-4) - 19 = 1
⇒ Solution = <u>(-4, 1)</u>
Answer:
240
Step-by-step explanation:
5(x² - 1)
5 ((-7)² - 1)
5(49 - 1)
5 (48)
A simpler form of this expression would be 19y-9
Answer:
For a sample size of 10, the t-value is about 3.25 (from tables) at a 99% confidence interval.
Explanation:
When the standard deviation for the population is not known, the confidence interval estimate for the population mean is performed with the Student's t-distribution.
The confidence interval for the mean is calculated as

where

= sample mean,
s = sample standard deviation,
t = t-value (provided in tables),
n = sample size.
When reading the t-value, (n-1) is called the df or degrees of freedom.