kaa tolongin aku please, aku agak kebingungan tentang soal ini!🤗

<p><strong>Jawaban yang tepat adalah 4</strong></p><p><strong>Pembahasan:</strong></p><p>-4x - 2y + z = 3 ...(1)</p><p>x + 3y - 2z = -1 ...(2)</p><p>2x + y - 3z = -9 ...(3)</p><p>&nbsp;</p><ul><li>Eliminasi <strong>x </strong>pada Persamaan (1) dan (2)</li></ul><p>-4x - 2y + z = 3 |x1| &nbsp;-4x - 2y + z = 3</p><p>x + 3y - 2z = -1 |x4| &nbsp;4x + 12y - 8z = -4</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; ----------------------------- &nbsp;+</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 10y -7z &nbsp;= -1 ...(4)</p><p>&nbsp;</p><ul><li>Eliminasi <strong>x </strong>pada Persamaan (2) dan (3)</li></ul><p>x + 3y - 2z = -1 |x2| &nbsp;2x + 6y - 4z = -2</p><p>2x + y - 3z = -9 |x1| &nbsp;2x + y - 3z = -9&nbsp;</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; --------------------------- –</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 5y - z = 7 ...(5)</p><p>&nbsp;</p><ul><li>Eliminasi <strong>z </strong>pada Persamaan (4) dan (5)</li></ul><p>10y - 7z = -1 &nbsp;|x1| &nbsp;10y - 7z = -1</p><p>5y - z = 7 &nbsp; &nbsp; &nbsp; &nbsp;|x7| &nbsp;35y - 7z = 49</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; --------------------- –</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; -25y &nbsp; &nbsp; &nbsp;= -50</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;y &nbsp; &nbsp; &nbsp; = -50/-25</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<strong>y &nbsp; &nbsp; &nbsp; = 2</strong></p><p>&nbsp;</p><ul><li>Substitusi nilai <strong>y = 2 </strong>ke Persamaan (5)</li></ul><p>5y - z = 7</p><p>5(2) - z = 7</p><p>10 - z = 7</p><p>-z = 7 - 10</p><p>-z = -3</p><p><strong>z = 3</strong></p><p>&nbsp;</p><ul><li>Substitusi nilai <strong>y = 2</strong>, dan <strong>z = 3</strong> ke Persamaan (2)</li></ul><p>x + 3y - 2z = -1</p><p>x + 3(2) - 2(3) = -1</p><p>x + 6 - 6 = -1</p><p><strong>x = -1</strong></p><p>&nbsp;</p><p>x = -1, y = 2, z = 3</p><p><strong>Jadi, x + y + z = (-1) + 2 + 3 = 4</strong></p>