Question 816887
{{{ -9 < 4x -1 < 15 }}} 

So we solve for x, but, we keep x in the middle. 

{{{ -9 + 1 < 4x -1 + 1 < 15 + 1 }}} 

This is what one gets when the 1 is taken out notice that the 1 is added to both sides.  

{{{ 8 < 4x < 16 }}} 

Then finally we have divide the 4 out, which we do to both sides. 

{{{ 8/4 < 4x/4 < 16/4 }}} 

Which leaves us with the final answer. 

{{{ 2 < x < 4 }}}