In January 2011, the national average for 5 gallons of gasoline was $17.20. Please hurry
1 answer:
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9514 1404 393
Answer:
(x, y) = (3, 7)
Step-by-step explanation:
If you divide the second equation by 2, it becomes ...
-x +2y = 11
Adding this to the first equation gives you the value of y:
(x -y) +(-x +2y) = (-4) +(11)
y = 7 . . . . . . . . simplify
The first equation can be rearranged to give an expression for x:
x = y -4
x = 7 -4 = 3
Then the solution is seen to be (x, y) = (3, 7).
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Personally, I like a graphing calculator for a quick and easy solution to many linear systems. (If the solutions are non-integers, it may not be so helpful.)
