Subtract the following algebric expression 2x+4y from 9x+7y

Δabc is reflected across line l to form δ alblcl, and a¯¯¯al¯¯¯¯ intersects line l at point d. which equation is not necessarily true?

Can someone check if i did this correct. it’s number 4 if you’re wondering.

How do you create a data set with 8 points in it that has a mean of approximately 10 and a standard deviation of approximately 1?