If x varies directly as y and x = 74 when y = 10, find x when y = 4.

The value of x is 21 .

Step-by-step explanation:

We are given that x varies directly as y

--- A

We are given that x = 7 and y = 28

Substitute the values in A

7 = 28k

Now equations becomes :  

y = 84

Hence The value of x is 21 .

#Learn more:

Find the value of y for a given value of x, if y varies directly with x.

If y = −252 when x = 84, what is y when x = 74

Step-by-step explanation:

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.