I am like spamming but I need help with 3 more!

Two planes leave an airport at the same time, one flying east, the other flying west. the eastbound plane travels 20 mph slower. they are 1600 mi apart after 2 hr. find the speed of each plane.

Can someone me with these two circle theorem questions asap?

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.