Let W be the union of the second and fourth quadrants in the​ xy-plane. That​ is, let W= x y : xy≤0. Complete parts a and b below. a. If u is in W and c is any​ scalar, is cu in​ W? Why? A. If u= x y is in​ W, then the vector cu=c x y = cx cy is in W because (cx)(cy)=c2(xy)≤0 since xy≤0. B. If u= x y is in​ W, then the vector cu=c x y = cx cy is not in W because cxy≥0 in some cases. C. If u= x y is in​ W, then the vector cu=c x y = cx cy is in W because cxy≤0 since xy≤0.

y = 0.77(x)

step-by-step explanation:

the jacket retains this value after 23% cut or retains 77% of original value. plug original 87 jacket price for x and the remaining value should be y.

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'.

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!