The rule for regular polygons are very easy. The number of reflectional symmetries is same as the number of sides. Regular polygons have all sides the same length and all angles same. Reflection symmetry means that you can fold the shape along that line and it will match up.
For this question, we want the number of reflectional symmetries of a regular decagon. Decagon is a 10 sided figure. Hence, the number of reflectional symmetries is 10.
There are 5 symmetry lines from one vertex to opposite vertex and 5 more symmetry lines form midpoint of one side to midpoint of opposite side.
ANSWER: 10
Answer: chicken $8, duck $5
Explanation:
x - the cost of a chicken
y - the cost of a duck
he sold 50 chickens and 30 ducks for $550: 50x + 30y = 550
he sold 44 chickens and 36 ducks for $532: 44x + 36y = 532
50x + 30y = 550 divide by 10
44x + 36y = 550 divide by 4
______________
50x/10 + 30y/10 = 550/10
44x/4 + 36y/4 = 532/4
______________
5x + 3y = 55
Multiply by (-3)
11x + 9y = 133
______________
5x * (-3) + 3y * (-3) = 55 * (-3)
11x + 9y = 133
______________
-15x - 9y = -165
11x + 9y = 133
______________
Sum up:
-4x + 0y = -32
-4x = -32
x = -32/-4
x = 8
Since 5x + 3y = 55 and x = 8, then:
5 * 8 + 3y = 55
40 + 3y = 55
3y = 55 - 40
3y = 15
y = 15/3
y = 5
Hi there!
f(x) = -2x - 3
Plug in 0 for "x" to solve for f(0):
f(0) = -2(0) - 3
f(0) = -3
Since the question is asking you to evaluate f(0) - 7, simply subtract:
-3 - 7 = -10.
