Hi i have been offered a dell 5100?

If thats a single core 3.4, i would not use that for any type of editing software. You will need at least a 3.0 Dual core, i would recommend if you can afford it to buy a Quad core or even an Intel i5-7 for Multi threading capabilities. Intel are more suited to the software suites you will be using as they can pull a greater load from running CPU heavy programs like that.