Answer: option d.
Step-by-step explanation:
If <em>y </em>varies directly as <em>x</em> and <em>z</em>, the form of the equation is:

Where<em> k</em> is the constant of variation.
If y=4 when x=6 and z=1 then substitute these values into the expression and solve for <em>k:</em>

<em> </em>Substitute the value of <em>k</em> into the expression. Then, the equation is:

To find the value of <em>y </em>when x=7 and z=4, you must substute these values into the equation. Therefore you obtain:


<em> </em>
This photo is the explanation
First we need to get x
<RNA = <ENV [v.o.a]
8x+12=5x+57
8x-5x=57-12
3x=45
x=15
<ENV= (5×15+57)
<ENV =132
the answer is D
You want to start at -2 on the y line wich is the vertical line then 1/5 is rise over run so you rise (go up) one and run ( go right)5