章节大纲

  • 常规

    全部折叠 展开全部

  • 识别等等价表达式

    In This Lesson
    ::在本课程中

    Y ou will be learning about . Two expressions are equivalent if they can be simplified to the same third expression or if one of the expressions can be written like the other. In addition , you can also determine if two expressions are equivalent when values are substituted in for the variable and both arrive at the same answer. 
    ::您将会学习 。 如果两个表达式可以简化为同一个第三个表达式,或者如果其中一个表达式可以像另一个表达式一样写成, 则两个表达式是等同的。 此外, 您还可以确定两个表达式是否等同, 当变量中的值被替换时, 并且两个表达式都达到相同的答案 。

     

    Matching Expressions
    ::匹配表达式

    In this interactive, there is a column of expressions and a box with other expressions. Your job is to drag the expressions in the box to its equivalent expression in the column. The first one is done for you.
    ::在此互动的表达式中, 有一列表达式, 和一个含有其他表达式的框。 您的任务就是将框中的表达式拖到列中的等同表达式。 第一个是为您完成的 。

     

    INTERACTIVE
    Matching Expressions
    minimize icon
    • Drag each expression on the top to the appropriate spot on the right so that it equals the expression on its left.
      ::将顶部的每个表达式拖到右边的适当位置,使其等于左边的表达式。
    Your device seems to be offline.
    Please check your internet connection and try again.
    +
    Do you want to reset the PLIX?
    Yes
    No

     

     

    Progress
    0 / 0

     

    When  simplifying and expanding expressions, you could find several expressions that are equivalent. Such was the case in #1 in the interactive. Many times, only a common factor may be factored out, instead of the GCF, or sometimes a fraction could be factored out. In addition, there could be multiple terms with the , and then even more equivalent expressions are possible.  
    ::当简化和扩展表达式时, 您可以找到一些等效的表达式 。 在互动的 # 1 中就存在这种情况。 许多次中, 只有一个共同因素可以被考虑出来, 而不是绿色气候基金, 或者有时一个小点可以被考虑出来。 此外, 还可以有多个词, 然后再有更多等效的表达式 。

     

    Are You Equivalent?
    ::你是同等的吗?

    Analyze the expression,  4 ( x − 3 ) − 2 ( 5 x + 6 ) + 10 . In the box, there are several other expressions that may or may not be equivalent to it. Sort them it the Yes or No columns, depending on if they are or are not equivalent to  4 ( x − 3 ) − 2 ( 5 x + 6 ) + 10 . 
    ::分析表达式, 4 (x- 3) - 2( 5x+6)+10。 在框中, 有几个其他表达式可能或可能不等同于它。 依它们是否等于 4( x- 3) - 2( 5x+6)+10 而定, 将其排序为 " 是 " 或 " 不 " 列。

     

    INTERACTIVE
    Are You Equivalent?
    minimize icon
    • Drag the expressions on the right to the correct spot whether or not it equals the expression on top.
      ::将右侧的表达式拖到正确位置,无论它是否等于顶部的表达式。
    Your device seems to be offline.
    Please check your internet connection and try again.
    +
    Do you want to reset the PLIX?
    Yes
    No

     

     

     

    You can substitute in nearly any value for the variable when trying to determine if two expressions are equivalent. The only number you cannot use is zero because, as you saw, it could give you an incorrect answer. When substituting in values for the variable, be careful and use the order of operations!
    ::在试图确定两个表达式是否等同时,您可以用几乎任何值来替代变量。唯一不能使用的数字是零,因为正如您所看到的,它会给您一个错误的答案。当变量的值被替换时,请小心使用操作顺序 。

       Summary
    ::摘要

    T wo expressions are equivalent if:
    ::两个表达式等同,如果:

    • T hey can both be simplified to equivalent expressions.
      ::两者均可简化为等同表达式。
    • Substituting a  value  into both expressions result s in  the same number .
      ::将一个值替换为两个表达式的结果相同。

    Remember : When using substitution, do not use zero.
    ::记住: 使用替代时, 不要使用零 。