Question

evaluate when e = 3 1/2.b=6.7 t=8.0

e-b + t

Answer 1

3.5 (E) - 6.7 (B)+ 8 (t)= 18.2

Answer 2

e - b + t

Now, Just substitute the known values, 
= 3 1/2 - 6.7 + 8.0
= 7/2 + 1.3
= 3.5 + 1.3
= 4.8

In short, Your Answer would be: 4.8

Hope this helps!