What will it be after n hours? here is an image to help. thanks! :)

The sum of two numbers is 86, and their difference is 20. find the two numbers

Write the expression 7x^3-28xy^2 as the product of 3 factors

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.