fix errors

tuplas/src/main.rs

@@ -13,9 +13,9 @@ fn main() {
 
     println!("{}", tup.0);
 
-    let mut cambiar = (1.1f32, 1);
+    let mut _cambiar = (1.1f32, 1);
     let aesto = (3.14f32, 6);
-    cambiar = aesto;
+    _cambiar = aesto;
 
     println!("{}", aesto.0);