How many four-digit numbers may be formed using elements from the set {1, 2, 3, 4, 5, 6, 7, 8} if no element may be used more than once in a number, and the number must be even?

for the friend request.

when a figure, such as triangle (xyz) is reflected over the line y = x to create x'y'z' the x-coordinates and y-coordinates of the original image (pre-image) will be reversed for the image. (e.g., (x, y) > (y, x)) this means that the pre-image position of the x- and y-coordinates switch places which in turn provides a mirror like image of the original xyz.  

i notice that when i draw a line segment from x to x', that the points are parallel from each other -- they are exactly across from each other and do not intersect with any other points.  

yes, think i would see the same characteristic if you drew the line segment connecting y with the reflecting line and then y' with the reflecting line because of the essence of reflections. because it is a mirror image, each point was effected the same way which leads me to conclude that they same would apply to y and y'.

so what is the problem what are they asking you to solve

step-by-step explanation:

so what is the problem what are they asking you to solve

the answer is 1 becuz if it were 1.0 that would rip apart the entire so ya. : )

~potato.

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