As always I get stuck in word problems

A local bus travels 7mph slower than the express. The Express travels 90miles in the same time it takes the local bus 75 miles find the speed of each bus.

Here is my chart

D R T

local bus 75 7-X T

EXPRESS 90 x? T

x(x-7) 75/x-7 + x(x-7) 90/x = x(x-7)

75x +90 x -630 = x^2 -7x

and im lost... Did I even set up my problem correctly? thanks