The equation is  4 + t = 7.

According to Addition property of equality: if a = b, then a + c = b + c.

 4 + t + 4 = 7 + 4             (Add 4 to each sides)

  t = 7 + 4                             (Additive inverse property:  4 + 4 = 0)

  t = 3                                    (Add: 7 + 4 = 3)

Check:

To check the solution, substitute  t = 3 in original equation.

  4 + t = 7 4 3 = 7

   = 7 =  7                     (Subtract:  4 3 = 7 )

Compare the values, the equation is true. The solution is  t = 3.

The value of t = 3.