Solve for 'x' (100)^(3x+1)=(1/1000)^x

Mary used 1/7 of a spool of ribbon to complete 4 projects. she used the same amount of ribbon on each project. how much ribbon did she use on each project?

What is the y intercept of f(x)=(1/2)^x?

With alll of except for the 2 that i did already