I can't import tensorflow-gpu

The package on pypi is called tensorflow-gpu but you just import it with "tensorflow"

 import tensorflow as tf

To ensure that the tensorflow package is using your GPU, do this:

import tensorflow as tf

sess = tf.Session()

See the output on the console, if it shows your GPU information on creation of the session as shown below.

Notice "GeForce 940MX" in the information. Also note that Tensorflow will use a Nvidia GPU only if the compute capability score is above 3.5 . More about that here.

If it's not using the GPU, then it won't output GPU information, it'll just show something similar to this: