An aeroplane takes 1 hour less for a journey of 1200 km if its speed is increased by 100km/h from its usual speed. find the time it takes to cover the distance.

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !

Can someone answer this question for me