1). 2x-1=5 (cause x can really be anything) solve the equation to get x=3 or in this case, triangle = 3.
2). Using the info from above, we get the equation 3+x=1.
Solving this equation we get, x (square) =-2.
3). Using all the info from the above problems we get the equation: 3-2*-2=x
Solving that we see that x (star) equals 7.
In conclusion:
Triangle=3
Square=-2
Star=7