Yes it is possible.

Let displace the block  right  side by x, 

then, force due to spring 1 is (k1)x and due to other is (k2)x  because elongation in Spring 1 is x and compression in  spring 2 is also x.

Total force is,

       = (k1x+k2x)

      =(k1+k2)x

So, the equivalent Spring Constant is (k1+k2) .