Answer:
a) x(x-2)
b) 6x(2x+2)
dont know c and d sorry
Step-by-step explanation:
Hi there!
![\large\boxed{(-\infty, \sqrt[3]{-4}) \text{ and } (0, \infty) }](https://tex.z-dn.net/?f=%5Clarge%5Cboxed%7B%28-%5Cinfty%2C%20%5Csqrt%5B3%5D%7B-4%7D%29%20%5Ctext%7B%20and%20%7D%20%280%2C%20%5Cinfty%29%20%7D)
We can find the values of x for which f(x) is decreasing by finding the derivative of f(x):

Taking the derivative gets:

Find the values for which f'(x) < 0 (less than 0, so f(x) decreasing):
0 = -8/x³ - 2
2 = -8/x³
2x³ = -8
x³ = -4
![x = \sqrt[3]{-4}](https://tex.z-dn.net/?f=x%20%3D%20%5Csqrt%5B3%5D%7B-4%7D)
Another critical point is also where the graph has an asymptote (undefined), so at x = 0.
Plug in points into the equation for f'(x) on both sides of each x value to find the intervals for which the graph is less than 0:
f'(1) = -8/1 - 2 = -10 < 0
f'(-1) = -8/(-1) - 2 = 6 > 0
f'(-2) = -8/-8 - 2 = -1 < 0
Thus, the values of x are:
![(-\infty, \sqrt[3]{-4}) \text{ and } (0, \infty)](https://tex.z-dn.net/?f=%28-%5Cinfty%2C%20%5Csqrt%5B3%5D%7B-4%7D%29%20%5Ctext%7B%20and%20%7D%20%280%2C%20%5Cinfty%29)
Answer:
£22
Step-by-step explanation:
Area to be painted
4walls - door
a = 4(2.6 * 3.5) - 2.2 * 0.8
a = 34.64 m²
Paint needed
p = 34.64 / 8
p = 4.33
Must round up
p = 5 liters
Tins needed
t = 5/2
t = 2.5
must round up
t = 3
Cost
since 1 is free with 2 will pay for 2
c = 11 * 2
c = 22
£22
Answer:
Step-by-step explanation:
5) -7 (-15w + 21) + 3(18 - 27w)
Step 2: 105w - 81w - 147 + 54
6)
step 3: 24w - 93