Bis the midpoint of ac and d is the midpoint of ce solve for x given bd equals 3x +5 and ae equals 4x +20?

On a piece of paper graph f(x)=5•(0.4)^x

Could someone with number 1 and 2

Starting at home, emily traveled uphill to the hardware store for 606060 minutes at just 666 mph. she then traveled back home along the same path downhill at a speed of 121212 mph. what is her average speed for the entire trip from home to the hardware store and back?