Which of the following create volcanoes?

they explode and make ash everywhere

Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.

this is all i know about volcanoes and how they are created

(4,-2)

explanation:

6x+4y=16

-6x-9y=-6

-5y=10

y=-2

x=4