下表显示了 3 个男孩收集的贝壳数量。

它不会直接告诉你答案，而是问你卡在哪一步看看 AI 是怎么陪你一步步弄懂这道题的

完整解法

1. Form an expression for the total number of seashells

$\text{Total} = 17 + x + (6x - 5)$

2. Simplify the algebraic expression

$\text{Total} = x + 6x + 17 - 5 = 7x + 12$

答案

$7x + 12$

1. Calculate the total number of seashells from the given average

$\text{Total seashells} = 39 \times 3 = 117$

2. Set up and solve the equation for $x$

From part (a), the total is $7x + 12$ .
$7x + 12 = 117$
$7x = 117 - 12$
$7x = 105$
$x = \frac{105}{7} = 15$

答案

$15$

AI 分析，可能出错

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