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Solve using the method of elimination , determine if the system has 1 solution, no solutions, or infinite solutions

-8x+2y=8
4x+8y= -4

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2 Answers

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\stackrel{\textit{2nd equation }* 2}{\begin{array}{rrrrr} -8x&+&2y&=&8\\ 2(4x&+&8y)&=&2(-4) \end{array}}\qquad \implies \qquad \begin{array}{rrrrr} -8x&+&2y&=&8\\ 8x&+&16y&=&-8\\\cline{1-5} 0&+&18y&=&0 \end{array} \\\\\\ 18y=0\implies y=\cfrac{0}{18}\implies \boxed{y=0} \\\\\\ \stackrel{\textit{we know that}}{4x+8y=-4}\implies 4x+8(0)=-4\implies 4x=-4\implies x\cfrac{4}{-4}\implies \boxed{x=-1} \\\\[-0.35em] ~\dotfill\\\\ ~\hfill \stackrel{\textit{one solution}}{(-1~~,~~0)}~\hfill

you'd want to often enough check their slopes first, if the slopes differ, they meet, if equal, they're parallel and either never meet or meet everywhere.

User Ashis Biswas
by
6.9k points
6 votes
Here is the work, the answer is no sol
Solve using the method of elimination , determine if the system has 1 solution, no-example-1
User MarkSkayff
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7.2k points
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