Combine like terms to simplify the expression: 9 + 3b − 1 + 7b − 2 =

16b

9 − 10b

6 + 10b

9 + 10b

8 + 10b

please help

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?

The image of the point (-6, -2)under a translation is (−7,0). find the coordinates of the image of the point (7,0) under the same translation.

Mary used 1/7 of a spool of ribbon to complete 4 projects. she used the same amount of ribbon on each project. how much ribbon did she use on each project?