how do I solve 5n^2=20n

n=0 and n=4

5n^2=20n    subtract 20n from both sides

5n^2 - 20n =  0       factor

5n(n - 4) - 0      set both factors to 0

5n= 0       divide both sides by 5

n = 0

And  n - 4 = 0     add 4 to both sides

n = 4

So..... n= 0 and n = 4