
Hope I helped, also, I used the math thingy, which I haven't used before, so I'm not sure quite how this turned out, well, I guess we will see in a minute! But if it does not work I can try it just typing regularly.
Y=90x+2,000
90 is the rate of change because the hot air balloon descends 90 feet per minute.
And 2,000 is the starting point because the hot air balloon started the descent at 2,000 feet.
They have the same number of valence electrons which, in general, gives them similar oxidation numbers and other similar chemical and physical properties. The similarities are most pronounced in the groups at either side of the standard periodic table, and are least pronounced for the transition and rare earth elements.
Factorization
completing square
quadratic formula