Answer:
A) 
B) T = -5 °C
Step-by-step explanation:
A) Let T be the change in temperature of the week. T is determined as the total temperature change (-20°C) divided by the number of weeks that have passed (4 weeks). The expression is:

B) In order to simplify the expression, simply perform the division.

This means that the temperature has dropped by 5 degrees each week.
The equation for standard deviation is finding the mean of the numbers, subtracting each of the initial numbers by the mean, squaring each of the results, finding the mean of these results added together, then finding out the square root of the results added together.
The mean of 175 and 165 is 170, subtract 175 and 165 by 170, and you get 5 and -5 respectively. Then, square the results and you get 25 and 25.
Add the two numbers together (25 & 25) then find the square root of it, which is <span>7.07106781187, simplified to 7.07.</span>
Answer:

Step-by-step explanation:

Answer:
idk
Step-by-step explanation:
Hello!
Remember that the symbols: ≤ and ≥ are graphed as a solid line. While the symbols: < and > are graphed as a dotted line.
Also, before graphing, it would be better to convert both equations to slope-intercept form.
y ≤ x + 1 is already in slope-intercept form.
y + x ≤ -1 is not written in slope-intercept form. (Slope-intercept form: y = mx + b)
y + x ≤ - 1 (subtract x from both sides)
y ≤ -x - 1
Graphing those lines, you get the graph below. You can see that Part C best represents the solution set systems of inequalities, because that is where both of the shaded lines intersect.
Answer: Part C