Abox contains both cubes and five-sided pyramids. the total number of objects in the box is 17. the total number of sides for the cubes and pyramids is 95. how many cubes are in the box? 6

We have the equation s

x + y = 17 
4x + 5y = 95       where x = number of cubes and y = number of pyramids

multiplying the first equation by -4:-
-4x - 4y = -68  Add this to the second equation:-
y = 27
Plug this into the first equation;-

x + 27 =  17 

x = -10 

There must be an error in your question because you can't have a negative number of cubes!!