does anyone know if this is poison ivy??

i was walking through the yard on the side of my house (or maybe i was really just creeping to admire my neighbors’ amazing landscaping) and when i got to the backyard, i found this plant sprouting up in a few different places.  actually… it’s kind of invading half of my backyard, as you can see from the last picture.  so… what do you think it is?  poison ivy/oak?