We have not discussed methods by which systems of first-order differential equations can be solved. Nevertheless, systems such as dx dt = −λ1x dy dt = λ1x − λ2y dz dt = λ2y (which is discussed here) can be solved with no knowledge other than how to solve a single linear first-order equation. Suppose that time is measured in days, that the decay constants are k1 = −λ1 = −0.135229 and k2 = −λ2 = −0.004951, and that x(0) = 20, y(0) = 0, z(0) = 0. Use a graphing utility to obtain the graphs of the solutions x(t), y(t), and z(t) on the same set of coordinate axes. Use the graphs to approximate the half-lives of substances X and Y. (Round your answer to the nearest integer.) X days Y days

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'.

nlgqer

step-by-step

the first one is x^2+2x+2

the second one is x^2+4

the last one is x^2-4x+8