What is the y intercept for a vertical line x equals 4

What is the product of the radical expression. (7-2square root) (8+2 square root)

If you were constructing a triangular frame, and you had wood in the length of 4inches, 4 inches, and 7 inches, would it make a triangle? would you be able to create a frame from these pieces of wood? yes or no. explain your mathematical thinking

In a sale there is 25% of all prices a chair costs £45 in sale how much was it before the sale