9. what's the most common extrusive igneous rock on earth?

The most common extrusive igneous rock on Earth  is BASALT.

Explanation:

Basalt is also the most common type of rock on the surface of the earth. The extrusive igneous rock on earth is another term used in reference to the word volcanic.

The rocks are formed when magma moves through the centre opening making its way down to earth's surface as lava. When it cools off it then takes its shape as rocks. The process is so slow that sometimes it might take many years.It primarily consists of pyroxene and  plagioclase  minerals

(4,-2)

explanation:

6x+4y=16

-6x-9y=-6

-5y=10

y=-2

x=4