David drives 168 miles a week he fill his tank 2 times a week each fill up is 12 gallons what is gas mileage on his car
2 answers:
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Answer:
Step-by-step explanation:
The given system is:
Since I prefer to use smaller numbers I'm going to divide both sides of the first equation by 3 and both sides of the equation equation by 6.
This gives me the system:
We could solve the first equation for and replace the second
with that.
Let's do that.
Subtract on both sides:
So we are replacing the second in the second equation with
which gives us:
Now recall the first equation we arranged so that was the subject. I'm referring to
.
We can now find given that
using the equation
.
Let's do that.
with
:
So the solution is (8,-1).
We can check this point by plugging it into both equations.
If both equations render true for that point, then we have verify the solution.
Let's try it.
with
:
is a true equation so the "solution" looks promising still.
with
:
is also true so the solution has been verified since both equations render true for that point.