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If the point (a,3) lies on the graph of the equation 5x + y = 8, then a=

A) 1
B) -1
C) 7

User Matt Morey
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2 Answers

7 votes

5a+3=8\\ 5a=5\\ a=1\Rightarrow A
User Tobyb
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4 votes

(a,3) \\ x=a \\ y=3 \\ \Downarrow \hbox{plug the values into the equation} \\ 5a+3=8 \ \ \ |-3 \\ 5a=5 \ \ \ |/ 5 \\ \boxed{a=1} \Leftarrow A
User Ayyash
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