Answer:
y = 
Step-by-step explanation:
Given that y varies directly as x then the equation relating them is
y = kx ← k is the constant of variation
To find k use the condition y = 7 when x = 3
k =
=
, thus
y =
x ← equation of variation
When x = 7, then
y =
× 7 = 
Answer:
x=9
Step-by-step explanation:
Equation: 5.60x=50.40
Solve: 5.60x=50.40
Divide both sides by 5.60 ( 5.60x/5.60 ) and ( 50.40/5.60 )
x=9
the student has left 75 because if you add 5 and 70 it gives you $75 that's how much the student had left.
About 1920, just find the volume by multiplying length times width times height
and divide that by the 1-inch cubes. hope this helps