|z−7|−|z−9| , if z< 7?
rewrite without using absolute value

Ametalworker has a metal alloy that is 30? % copper and another alloy that is 55? % copper. how many kilograms of each alloy should the metalworker combine to create 90 kg of a 50? % copper? alloy?

What is the product of the radical expression. (7-2square root) (8+2 square root)

Write a similarity statement for the similar triangles. afgh ~ a