<u>Question 8</u>
a^2 + 7a + 12
= (a+3)(a+4)
When factorising a quadratic, the product of the two factors should equal the constant term (12), and the sum of the two factors should equal the linear term (7). To find the two factors, list out the factors of 12 (1x12, 2x6, 3x4) and identify the pair that adds up to 7 (3+4).
An alternative method if you get stuck during your exam would be to solve it algebraically using the quadratic formula and then write it in the factorised form.
a = (-7 +or- sqrt(7^2 - 4(1)(12)) / 2(1)
= (-7 +or- sqrt(1))/2
= -3 or -4
These factors are the negative of the values that would go in the brackets when written in factorised form, as when a = -3 the factor (a+3) would equal 0. (If it were positive 3 instead, then in the factorised form it would be a-3).
<u>Question 10</u>
-3(x - y)/9 + (4x - 7y)/2 - (x + y)/18
Rewrite each fraction with a common denominator so you can combine the fractions into one.
= -6(x - y)/18 + 9(4x - 7y)/18 - (x + y)/18
= (-6(x - y) + 9(4x - 7y) - (x + y)) /18
Expand the brackets and collect like terms.
= (-6x + 6y + 36x - 63y - x - y)/18
= (29x - 58y)/18
= 29/18 x - 29/9 y
Answer:
The data is a simple random sample from the population of interest.
Step-by-step explanation:
Conditions necessary to consider when constructing a confidence interval include using a large sample size, which should be greater Than or equal to 30 for n and a sample proportion of np ≤ 10. Importantly the sample must be a random sample drawn from the population, meaning that all the population of interest must have equal chances of being a part of the sample data. However, the scenariomabiveb, violates this condition as the sampling design is not completely randomized. Those who do not ply the route on that certain day have no Chaves of being part of the sample.
Answer:
The sample proportion of printers used in small business is:
The 95% confidence interval for the population proportion of printers that are used in small businesses is:
Where:
is the critical value at 0.05 significance level
Therefore, the 95% confidence interval for the population proportion of printers that are used in small businesses is (0.245 , 0.469)
The answer is $911.68.
After a little research on the internet, I found the design of the window.
First, you need to find the area of the window which is a composite figure made up of a rectangle and a circle. So, the total area (A) is the sum of the area of the rectangle (A1) and the area of the circle (A2).
Area of the rectangle with length l and width w is:
A = l * w
According to the image, l = 5 ft and w = 4 ft.
A1 = 5 * 4 = 20 ft²
Area of the circle with radius r is:
A = r²π
According to the image, r = 2 ft.
A2 = 2² * 3.14 = 12.56 ft²
The area of the window is:
A = A1 + A = 20 ft² + 12.56 ft² = 32.56 ft²
<span>The glass costs $28 per square foot, so to replace the glass will cost:
</span>32.56 ft² * $28/ft² = $911.68
