Solve by elimination: |
\[3x-y=7\] |
\[2x+5y+1=0\] |
Answer:
\[3x-y=7\] ...(i) \[2x+5y=-1\] ...(ii) Multiplying equation (i) by 5 and solving it with equation (ii), we get \[_{\begin{smallmatrix} 15x\,-\,5y\,=\,35 \\ \overline{17x\,\,\,\,\,\,\,\,\,\,\,\,\,=\,34\,\,} \end{smallmatrix}}^{2x\,\,+\,\,5y\,\,=\,\,-1}\] (Adding) \[\Rightarrow x=\frac{34}{17}=2\] Putting the value of x in (i), we have \[3(2)-y=7\] \[\Rightarrow 6-y=7\Rightarrow -y=7-6\] \[\Rightarrow y=-1\] \[\therefore \,\,x=2,y=-1\]
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