Simplify each and state the excluded values ​

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20

Three baby penguins and their father were sitting on an iceberg 0.50.50, point, 5 meters above the surface of the water. the father dove down 4.74.74, point, 7 meters from the iceberg into the water to catch dinner for his kids. what is the father penguin's position relative to the surface of the water?

In a column proof the right column states your reasons