# 'Graphics' object is not callable

Sorry to ask anonymously a question but I cannot recover my account (...@...). . Why

```
var("x_2 z")
sol1=solve(4*x_1+ 3*x_2==z,x_2)
show(sol1)
obj1=sol1[0].substitute(z=10).rhs()
show(obj1)
plot(obj1,(x_1,0,100))
```

leads to `'Graphics' object is not callable`

?

Apart from the fact that i have to add some

`var("x_1")`

, it works well for me.