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) .