Describe how to determine whether or not two ratios are equivalent. Please help due at 11:59 !

3(10x-y)-5(x-y^2) need this solved asap

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'

If the altitude is drawn to the hypotenuse of a right triangle, then the two triangles formed are similar to the original triangle and to each other. which set of triangles shows the similar triangles created by the altitude in the diagram?