E ) a three-dimensional box-shaped figure, with six identical square faces
The width is half the length, so is
width = (1/2)*length
width = (1/2)*(<span>3.2a + 0.18b) cm
width = (1.6a +0.09b) cm
The perimeter of the rectangle is twice the sum of length and width.
perimeter = 2*(length + width)
perimeter = 2*((3.2a +0.18b) cm + (1.6a +0.09b) cm)
perimeter = 2*(4.8a +0.27b) cm)
perimeter = (9.6a +0.54b) cm
Sasha did not get this answer, so apparently ...
her reasoning was not correct.</span>
<span>(serial number, model number)
That's a function mapping each serial number to its model number.
(part number, serial number)
That's not a function; the same part number is in computers with different serial numbers
</span><span> (model number, part number)
</span><span>
That one's a bit confusing. Normally a given model would have more than one part number inside so this isn't a function. But here the description says there's only one part number for each model, so that would be a function.
(model number, serial number)
Not a function, more than one serial number for a given model number.
</span>
Answer:
- Andre subtracted 3x from both sides
- Diego subtracted 2x from both sides
Step-by-step explanation:
<u>Andre</u>
Comparing the result of Andre's work with the original, we see that the "3x" term on the right is missing, and the x-term on the left is 3x less than it was. It is clear that Andre subtracted 3x from both sides of the equation.
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<u>Diego</u>
Comparing the result of Diego's work with the original, we see that the "2x" term on the left is missing, and the x-term on the right is 2x less than it was. It is clear that Diego subtracted 2x from both sides of the equation.
_____
<em>Comment on their work</em>
IMO, Diego has the right idea, as his result leaves the x-term with a positive coefficient. He can add 8 and he's finished, having found that x=14.
Andre can subtract 6 to isolate the variable term, and that will give him -x=-14. This requires another step to get to x=14. Sometimes minus signs get lost, so this would not be my preferred sequence of steps.
As a rule, I like to add the opposite of the variable term with the least (most negative) coefficient. This results in the variable having a positive coefficient, making errors easier to avoid.
Compab=a.b/|a|
b=<0,1,−2√10>
a.b= 2√10
|a| = √10
a.b/|a|=2√10 / √10=2