How many solutions are there to the equation below? 8(x-3) = 7x- 20
1 answer:
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Answer:
When the plane makes its turn to fly southeast, it makes a 45º angle at point a, making angle abc also equal to 45º.
Line ab is the 2 miles southeast the plane flies.
Line ac = line cb
sine (45º) = opposite / hypotenuse = cb / 2
.70711 = cb / 2
cb = 1.41422 miles = line ac
Line cs = 3 - 1.41422 = 1.58578
Line x^2 = cs^2 + cb^2
Line x^2 = 2.5146982084 + 2.0000182084
Line x^2 = 4.5147
Line x = 2.1248
Step-by-step explanation:
Answer:
65,280
Step-by-step explanation:
Consider the 4×4 grid ...
where each of a, b, c, d is a 2×2 array of tiles. Let's use the notation a' to represent the 2×2 array "a" rotated right 1/4 turn. For 90° rotational symmetry, we must have b=a', c=b'=a'', d=c'=b''=a'''. That is, once "a" is determined, the rest of the grid is determined. Since "a" consists of 4 tiles, each of which can be black or white, there are 2^4 = 16 patterns that have 90° rotational symmetry.
The same will be true of 270° rotational symmetry, for the same reason.
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For 180° rotational symmetry, we must have c=a'' and d=b''. Then the combination of "a" and "b" together fully determines the grid. Together, "a" and "b" consist of 8 tiles, so there are 2^8 = 256 ways to pattern the grid so it will have 180° rotational symmetry. (Of those, 16 have 90° symmetry, and 16 have 270° symmetry. The sets are overlapping.)
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The 16 tiles of the grid can be colored 2^16 = 65,536 different ways. As we have seen, 256 of those colorings result in 180° rotational symmetry. Then the number of colorings that have no rotational symmetry is ...
65,536 -256 = 65,280 . . . . colorings not rotationally symmetric