Weight machines for fat burning ... which is better? Need lo

I was taught that fewer reps with higher weight helps to build muscle mass. More reps with a lighter weight (often done at a faster pace as well) helps to tone and lose weight.

From a professional in the fitness industry:

Number one: your female, get off the weight machines. Think of it this way: What gets your car cleaner- machine or hand wash??? Free weights are your friend.

It could be:
You've Been Doing the Same Weight Circuit Since Forever
The reason it seems easy isn't because you're getting stronger and stronger. It's because your muscles, having adapted to the program, are utterly bored. "You need to continually challenge them," Bushman says. "Muscles improve only when they're doing something they're unaccustomed to."
The Solution: There are myriad ways to change things up. "Use the machines, free weights, resistance bands. You can manipulate the number of reps, amount of weight, length of rest periods between sets, number of sets, and the overall number of exercises," Bushman says. Try doing 12 to 15 reps of light weights one session, 8 to 10 reps of moderate weights the next, then 4 to 6 reps of heavy weights. "Ideally, you want to do something different every time you go to the weight room, or at least once every two weeks," Sforzo adds.

You Race Through Your Reps
Two things could be going on here: Either your weights are too light, which is often the case for women, or they're too heavy, and you're letting momentum or gravity take over. Either way, your muscles aren't being sufficiently challenged, which is why they're not getting more toned. "To see an improvement in definition, you need to have an increase in the protein content of muscle fibers, and that happens when the muscles are stressed and being called on to exert more force," Bushman explains.
The Solution: If you don't believe you've done just about all you can do by the end of a set, pick a heavier weight. "You want there to be a bit of strain on the second-to-last and last reps," Bushman says. Reach for a lighter dumbbell when you aren't moving the weight with steady control as you lift and lower.