Need technical advice: monitor speakers.(solved)

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Hi I just received my Studiophile AV 40 today to use with the M50 . I want to use the AV40 in a small audio environment to avoid unplugging the M50 lines out to my complex PA system.
Since the M50 has only two outputs : L/R lines out and Headphones out : [ 33 ohms ...32 +32 mW at 33 ohms]
1 : Can I use the headphones to drive the AV40 lines in without any danger using the M50 volume slider with precaution?

AV40 specs:input Impedance: 10 k Ω unbalanced, 20 k Ω balanced
input Sensitivity: 100 mV pink noise input produces 90dBA output SPL at 1 meter with volume control at maximum

2 : Or if I must use the M50 lines out would it be ok to use a Y split cable with the M50 L/R lines out...one branch toward the AV40 lines in an the other
branch to my PA mixer never using both systems at the same time?
Thanks.

I finally got an answer from M-Audio and even is the headphones usage might be ok in not damaging the monitors I could hear some distorsion using it so I just used two Y cables plugged into the M50 L/R lines out for a temporary solution until I get a small mixer to do the job.