题目内容
已知:
=
=
,则
=
.
| x |
| 2 |
| y |
| 3 |
| z |
| 4 |
| x+y+z |
| 2x |
| 9 |
| 4 |
| 9 |
| 4 |
分析:设
=
=
=t,则x=2t,y=3t,z=4t把代数式的x、y、z都用t代换,进一步化简求出数值即可.
| x |
| 2 |
| y |
| 3 |
| z |
| 4 |
解答:解:设
=
=
=t,则x=2t,y=3t,z=4t;
则
=
=
=
.
故答案为:
.
| x |
| 2 |
| y |
| 3 |
| z |
| 4 |
则
| x+y+z |
| 2x |
| 2t+3t+4t |
| 2×2t |
| 9t |
| 4t |
| 9 |
| 4 |
故答案为:
| 9 |
| 4 |
点评:考查了比例的性质,利用比例的性质,设出参数,把所有字母都用参数表示,进一步代入求的代数式的值.
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