Mark is solving the following system. X+Y+Z = 2
(1)
(2)
3x+2y+Z = 8
4x-y-72 = 16
(3)
Step 1: He multiplies equation (1) by 7 and adds it to equation (3).
Step 2: He multiplies equation (3) by 2 and adds it to equation (2).
Which statement explains Mark's mistake?
O He added equation (3) instead of equation (2) in step 1.
O He did not multiply equation (3) by the same number as equation (1).
O He did not eliminate the same variables in steps 1 and 2.
O He added equation the equations in step instead of subtracting them.

shorter then the tree

large crystals result from very slow cooling.

evaporation of water: this would produce an evaporite which is a sedimentary rock. like a salt pan in a desert. not possible to have volcanic rocks originate this way.

crystalization in molten earth: slow cooling over time. (hundreds to millions of years)

crystalization at earth's surface: this results in fast cooling. (a few hours to a few months or years)

crystalization from cooling off hot water: that would be a hydrothermal deposit. while associated with volcanics they are not volcanic rocks themselves and usually occur fairly rapidly.