It's very, very difficult to graph letters on the TI-84 Plus because many letters are not functions. For example, it is impossible to graph vertical lines using Y1, Y2, etc, because those are not functions.

But, after much strife (took me two days), I've found a way to graph the desired letters. First of all, you need to be in Parametric mode. Press [Mode] and change the settings from Func to Param.

You must also be in Radian mode. Press [Mode] and switch from Degree to Radian.

Bear in mind that you must be in the standard window dimensions in order for this to work properly, so you might want to press [Zoom] > 6:ZStandard before graphing.

If you would like the axes to be hidden while the functions are being graphed, you can do so by pressing [2nd][Zoom](Format) > AxesOff.

Press [Y=] and you should see X1T, Y1T, etc. Enter the following (you may want to write these down for when you will graph them on hers):

X1T = {-10,-6,3,7

Y1T = 1.5T−5

X2T = (2.5cos(T)−{10,6})/(T≥0 and T≤π/2 or T≥3π/2

Y2T = 2.5(1+sin(T

X3T = T−6

Y3T = (-5/3T)/(T≤2.8

X4T = 2cos(T

Y4T = 5sin(T

X5T = T+3

Y5T = abs(5/2T−5)/(T≤3.9

≤ and ≥ are located in [2nd][Math](Test).

' and ' and ' or ' can be located in [2nd][Math](Test) > Logic.

If you have any questions, you can send me a message through Y!A.

Best wishes!