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I need help with this question Solve for the first variable in one of the equation:Correct: EQ1 = x - 4y = -11

I need help with this question Solve for the first variable in one of the equation-example-1
User Kurt Telep
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1 Answer

13 votes
13 votes

Given the equations:


\begin{gathered} x-4y=-11 \\ 2x+y=23 \end{gathered}

For the first equation:


\begin{gathered} x-4y+4y=-11+4y \\ x=-11+4y \end{gathered}

Substitute x in the second equation:


2(-11+4y)+y=23

Simplify:


\begin{gathered} -22+8y+y=23 \\ -22+9y=23 \end{gathered}

Solve for y:


\begin{gathered} -22+9y+22=23+22 \\ 9y=45 \\ (9y)/(9)=(45)/(9) \\ y=5 \end{gathered}

Then, substitute y = 5 in x:


x=-11+4(5)=-11+20=9

Answer:

x = 9

y = 5

User Karina H
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