Quien me ayuda con eso le dare los puntos que sea porfa​

Write a real-world solution that can be represented by the equation y = 7x be sure to explain what the variables represented in the solution

What is the exact area of a circle with a diameter of 50 centimeters? a.87.9 square centimeters b.379.9 square centimeters c.1962.5 square centimeters d.4923.5 square centimeters

15 points ! ~ see if you know the answer to both you!