Answer:
B. x < -8 or x > 8
Step-by-step explanation:
You can use process of elimination to solve this problem by going through every solution and testing them out, but let's jump right to B.
Process:
You know that since the inequality states that x^2 has to be greater than 64, x has to be more than 8, or less than -8.
This is because 8^2 = 64, and -8^2 = 64, and the inequality requires the answer to be more than 64.
Looking at B., you can see that if x is < -8, the square of, for example, -9, would be 81. This is greater than 64, so this works!
Now, B. also has an alternative. The 'or' is a major clue to which is the correct answer, since the square root of any number can be positive or negative. (-8^2 = 8^2)
The 'or' states that x must be greater than 8. So, for example, if we take the square of 10, we get 100, and that is also greater than 64.
We've proven that this solution is accurate for both parts, so it is definitely the one we want!
Hope this helps!
Answer: 20 mph
Explanation:
Speed is a physical quantity which is equal to the ratio between the distance covered (d) and the time taken (t):
In the first part of the problem, the plane flew a distance of d=400 mi in a time of t=2.5 h. The speed of the plane in this case was the difference between the proper speed of the plane, v, and the speed of the wind, w, since the plane flew opposite to the wind. So we can write:
(1)
During the return trip, the plane flew with a speed (v+w), since the wind was on the tail, and it took 2 hours to cover the same distance:
(2)
So we have two equations with two unknown variables. From (1), we get
Substituting into eq.(2)
So, the speed of the wind was 20 mph.
Answer:
1. slope = 4 intercept = -2
2. slope = 2/3 intercept = -4
3. slope = -1 intercept = 13
Step-by-step explanation:
Answer:
12cm
Step-by-step explanation:
Width = 10 cm
Area = 120 cm²
Length = ?
Area = Length(L) × Width(W)
120cm² = L × 10cm
L = 120cm² ÷ 10 cm = 12cm
