Question

–x – 7 = 16 please help me

Answer 1

Move the -7 to the right, its sign will flip (do you know why?)
Negate both sides to change -x to x

-x = 16+7
-x = 23
x = -23

Answer 2

-x-7=16  |+7 , add to both sides
-x=23  |*(-1)
x = -23

Answer:
-23
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-x-7=-(-23)-7=23-7=16