Question

Im desperate to find the answer please give an explanation to how you got the answer

Answer 1

Just draw the graphs, and you should find y = 10x² is the only graph narrower than the given one.

Answer 2

In general the graph of ax^2  is the graph of x^2 wich is stretched by a factor a paralell to the y-axis. So the greater the value of a is the greater the stretch and the narrower the graph.

The answer :-  y = 10x^2 is the narrowest.