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【329772】5.8 三元一次方程组 同步练习1

时间:2025-02-05 18:07:30 作者: 字数:1096字


 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>

5.8 三元一次方程组

考点1:用代入法解方程组

1.方程x+2y-3z=0的解有 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> ……

2.方程组 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> 的解是( )

A.  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> B.  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> C.  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> D.  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>

3.用代入法解下列方程组

1 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>2 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>


考点2.用加减法解方程组

4.解三元一次方程组 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> 时,首先消去z,得二元一次方程组为___________________,再消去未知数x,得一元一次方程为_________________.解得y=_______;y代入变形得到的二元一次方程组中,求得x=_________,最后将xy值同时代入②;得z=__________.

5. 方程组 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> 中,未知数_________的系数成倍数关系,解此方程组首先考虑消去未知数______较简单,得到关于_______________的二元一次方程组为____________.

6. 解方程组 <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>x等于( )

A.18 B.11 C.10 D.9

7. 解下列三元一次方程组.

(1)  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> (2)  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>




参考答案

  1. x=- <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> , y=4, x=-9

  2. D

  3. (1)  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> (2)  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>

  4.  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> , 2y=6, y=3, x=2, z=1

  5. y,y,xz,  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>

  6. C

7.(1)  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a> (3)  <a href="/tags/48/" title="练习" class="c1" target="_blank">练习</a> <a href="/tags/50/" title="同步" class="c1" target="_blank">同步</a> <a href="/tags/380/" title="方程" class="c1" target="_blank">方程</a>