Answer:
(b) (x -10)(x +10)
Step-by-step explanation:
The factorization of the difference of squares is a special form:
a² -b² = (a -b)(a +b)
<h3>Application</h3>
Your expression is recognizable as the difference of squares:
x² -100 = x -10²
Using the above form, the factorization is ...
= (x -10)(x +10) . . . . . . . . matches the second choice
The GRE Scores are represented as ~N(310,12)
In order to find the proportion of scores between 286 and 322, we need to standardize the scores so we can use the standard normal probabilities. Thus, we will find the z-score.
By looking on the standard normal probabilities table, we find the proportion of scores less than -2.
P(z < -2) = 0.0228
Then, we find the proportion of scores less than 1.
P(z < 1) = 0.8413
To find the proportion between -2 and 1, we subtract the two.
P(-2 < z < 1) = 0.8413 - 0.0228 = 0.8185 = 81.85%
Therefore, 82% of scores are between 286 and 322
Answer: The diver is 23 feet under sea level
Step-by-step explanation:
If we draw a vertical number line (image attached), where point 0 is sea level (the diver's initial position), the first point under sea level is -20, since we are told it dives a distance of 20 ft (the negative sign is only to indicate the direction, since a distance cannot be negative).
Then, the diver goes 10 ft deep. This means now it is 30 ft under sea level and the second point is -30.
After that the diver swims up 12 ft, hence we have to count 12 points up in our number line and the corresponding point is -18.
Finally, the diver swims 5 ft lower and keep that position. Hence, we have to count 5 points below point -18 in the number line, resulting in the last point: -23.
This means the diver's final position is 23 feet under sea level.
If we want to prove it with numbers, we can do it as follows:
20 ft (down)+10 ft (down)-12 ft (up)+5 ft (down)=23 ft