Answer:
46
Step-by-step explanation:
Well $1o each than 10×4=40 and 40 +6=46
8 - 7x^2 + 3 = 4x^2 - 1
8+3-7x^2 = 4x^2-1
11-7x^2 = 4x^2-1
B. Commutative property of addition
We can swap numbers and obtain the same results.
In this case, we swapped 8+3 and added them.
The distribution of the number of occurrences of the letter t on the pages of a book is found to be a normal distribution with a mean of 44 and a standard deviation of 18. If there are 500 pages in the book, which sentence most closely summarizes the data?
A. The letter t occurs less than 26 times on approximately 170 of these pages.
B. The letter t occurs less than 26 times on approximately 15 of these pages.
C. The letter t occurs more than 26 times on approximately 420 of these pages.
D. The letter t occurs more than 26 times on approximately 80 of these pages.
.Answer:
<span>mean = 44 </span>
<span>sd = 18 </span>
<span>that means that "26" is 1 s.d. down, or at the 16th %ile </span>
<span>so, there is a .16 chance that "t" will occur less than 26 times on any single page. </span>
<span>consequently, there is a .84 chance that it will occur more than 26 times on any single page. </span>
<span>Using that information, and knowing that 16% of 500 is 80, and 84% of 500 is 420, can you see where "C" is correct? </span>
If you learned about the 45-45-90 triangle (which is isosceles), then the faster way is to know that the hypotenuse (side opposite of right angle) is √2 times either one of the sides.
3√2 = (√2)x
x = 3
But if you didn't learn the 45-45-90 triangle yet, that's ok.
Recall the trigonometric ratios for right triangles: sine (sin), cosine (cos), tangent (tan).
If your angle is x, then
sin(x) = opposite side / hypotenuse
cos(x) = adjacent side / hypotenuse
tan(x) = opposite side / adjacent side
Remember the hypotenuse is the side opposite and across from the right angle (3√2 in this case).
An acronym to remember this is SohCahToa.
In this problem, the angle given is 45°, and you need to find the length of the adjacent side x. The hypotenuse is also given as 3√2.
Because we have the adjacent side and the hypotenuse, we use cosine to relate those two sides
cos(45°) = x / (3√2)
x = (3√2)cos45°
If you plug this into your calculator (in degree mode), then
x = 3
