help

It appears to me that several values for x would work in number 1.  I don't know how to solve it.  Sorry. 

2.   Factor fully by grouping:   5x² + 15x +4x + 12  

I'm not sure what "by grouping" means, but I can factor the quadratic for you.  

First add 15x and 4x                5x² + 19x + 12  

This will factor to                      (5x + 4)(x + 3) 

_.    

I think we need the dimensions of the pool ....or the value of 'x' to calculate this

  without these ,   the answer I get is   

   area = 16x^2+8x