Determine the coordinates of the y-intercept of 5x − 5y = 4

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?

Solve the following simultaneous equation by using an algebraic method (either substitution or elimination) 2x + 3y=-4 4x-y=11

I’m on question 7 it says a covered water tank is in the shape of a cylinder the tank has a 28 inch diameter and a height of 66 inches to the nearest square inch what is the surface area of the water tank