What is the ratios 15cm: 5m lowest term?

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10

Write the summation to estimate the area under the curve y = 1 + x2 from x = -1 to x = 2 using 3 rectangles and right endpoints

Ihave 9 cowry shells if a dozen eggs(12 eggs) cost 2 cowry shells how many dozens can i purchase