What is metal ? Where does it coke from ?

Most pure metals, like aluminium, silver and copper, come from the Earth's crust. They are found in ores – solid materials called minerals, usually occurring in rock, from which the pure metal has to be extracted. The properties of pure metals can be improved by mixing them with other metals to make alloys.

m=9

step-by-step explanation:

7m+8=71 subtract   8 from 71 which is 63 than divide it by 7m   equal 9.