What is the volume of this aquarium for iready

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9

1. 2. ∠b and ∠y are right angles. 3.? 4.? which two statements are missing in steps 3 and 4? ∠x ≅ ∠c △abc ~ △zyx by the sas similarity theorem. ∠b ≅ ∠y △abc ~ △zyx by the sas similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem. = 2 △abc ~ △zyx by the sss similarity theorem.