You can solve this by setting up a proportion. 4/6 = x/9. Cross multiply to get 6x=36. Divide both sides by 6 to get x=6.
Answer:
x = 3
Step-by-step explanation:

Do you need a unit rate? Or do you have an attatchment for me to solve the unit rate? If you need an example of a unit rate one could be:
27 gallons.
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$3. Cost
27 divided by 3 is 9
9 gallons
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Per dollar
First you'd substitute x= y-3 in the first equation.
10(y-3) -10y= 1
10y - 30 -10y= 1
The y's cancel each other out, so you're left with -30= 1. That means there's no solution :)
Equation of a line is given by y - y1 = m(x - x1) where m is the slope and (x1, y1) is any point on the line.
y - (-2) = 4(x - 3)
y + 2 = 4x - 12
y = 4x - 12 - 2
y = 4x - 14