What is the energy flow of a existing Rock to Metamorphic Rock?

When existing rock is exposed to high temperatures and pressures, thermal energy is transferred to the rock by conduction. This causes the particles of the rock to be rearranged, resulting in the formation of metamorphic rock

look at the picture.

y-intercept for the function on a picture is 4 → point (0, 4).

y-intercept for the function

is for x = 0. substitute:

y-intercept is 8 → point (0, 8).