d contains terms x, y, and z. all three are different.
you want the sum of the distances to equal 1900 miles.
they are travelling in opposite directions and therefore the distances will add.
let the number of hours = t
d = r*t
635*t + 325*t = 1900 combine the right
960*t = 1900 divide by 960
960t/960 = 1900/960
t = 1.98 hours or 1 hour and 58.8 minutes or 1 hour 58 minutes 48 seconds.
without choices, i don't know which answer you want. perhaps even 2 hours is (rounded) close enough
1. which of the sets of terms below does not include like terms?