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Solve the system by substitution.-3x—6y=45 -5y=x

User Avimak
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1 Answer

17 votes
17 votes

The second equation already has the value of x isolated, so in order to solve the system by substitution, we can apply this value of x from the second equation in the first one:


\begin{gathered} x=-5y \\ \\ -3x-6y=45 \\ -3\cdot(-5y)-6y=45 \\ 15y-6y=45 \\ 9y=45 \\ y=(45)/(9)=5 \end{gathered}

Now that we have the value of y, we can find the value of x:


x=-5y=-5(5)=-25

So we have that x = -25 and y = 5.

User Angry Dan
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