Answer:
The fifth line contains the error.
Step-by-step explanation:
Line 1 is the equation.
Lines 2, 3, and 4 are correct.
The error is in the 5th line.
The square root of a negative number is not a real number, so if this problem is solved only with real numbers, there is no solution.
If imaginary numbers are allowed, then the last line should read:

3 x + 7 = 2
3 x = 2 - 7
3 x = - 5
x = - 5/3
3 ( -5/3) + 7 = - 15/3 + 7 = - 5 + 7 = 2
You can see how the difference between two consecutive terms is constantly increasing:




So, for the next terms we'll have to add +9, +11, +13 and so on.
Also, note that
is obtained by adding the 2nd odd number to
,
is obtained by adding the 3rd odd number to
, and so on.
So, the recursive formula is

For the explicit formula, recall that the sum of the first n odd numbers is n squared. Taking into account the fact that we're not starting from 1, we have

Considering it's dimensions and the formula, the volume of the cuboid is of 160 cm³.
<h3>What is the volume of a rectangular prism?</h3>
The volume of a rectangular prism, such as a cuboid, is given by the <u>area of the base multiplied by the height</u>, that is:
V = Ab x h
In this problem, the base is a square of sides 4 cm, with the height of 10 cm, hence the volume is given by:
V = 4² x 10 = 160 cm³.
More can be learned about the volume of a cuboid at brainly.com/question/22694657
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