Which system of equations has no solutions? (Systems of Linear Equations - Quiz I-ready)

What is the volume of this square pyramid?

At oaknoll school, 90 out of 270 students on computers. what percent of students at oak knoll school do not own computers? round the nearest tenth of a percent.

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /