Express this number in scientific notation

9 ten thousandths

If np3 /nc2 = 6, find the value of n

Felix wrote several equations and determined that only one of the equations has no solution. which of these equations has no solution?

Arectangular lawn is 14m long and 10m wide. a strip of uniform width is mowed around the outside of the lawn. how wide is the strip when the area of the unmowed portion of the lawn is 12m². (the answer is 4m, but i need to know how to solve it)