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# Which do you think is the best measure to use to assess their performance? explain.

• Réponse publiée par: elaineeee

Measuring instruments like ruler, laboraty apparatus, & etc.

• Réponse publiée par: axelamat70

what of answer of thousandths, hundredths, tenths, ten, and hundreds of 123.5201

step-by-step explanation:

• Réponse publiée par: kateclaire

subtracting polynomials is quite similar to adding polynomials, but there are those pesky "minus" signs to deal with. if the subtraction is being done horizontally, then the "minus" signs will need to be taken carefully through the parentheses. if the subtraction is done vertically, then all that's needed is flipping all of the subtracted polynomial's signs to their opposites.

step-by-step explanation:

simplify (x3 +   3x2 + 5x – 4) –   (3x3 – 8x2 – 5x + 6)

the first thing i have to do is take that "minus" sign through the parentheses containing the second polynomial. some students find it helpful to put a "1" in front of the parentheses, to help them keep track of the minus sign.

here's what the subtraction looks like, when working horizontally:

(x3 + 3x2 + 5x – 4) – (3x3 – 8x2 – 5x + 6)

(x3 + 3x2 + 5x – 4) – 1(3x3 – 8x2 – 5x + 6)

(x3 + 3x2 + 5x – 4) – 1(3x3) – 1 (–8x2) – 1(–5x) – 1(6)

x3 + 3x2 + 5x – 4 – 3x3 + 8x2 + 5x – 6

x3 – 3x3 + 3x2 + 8x2 + 5x + 5x – 4 – 6

–2x3 + 11x2 + 10x –10

and here's what the subtraction looks like, when going vertically:

\small{ \begin{array}{}x^3& +3x^2& +5x& -4\\-(3x^3& -8x^2& -5x& +6)\\ \hline\end{array} }

x

3

−(3x

3

​

+3x

2

−8x

2

​

+5x

−5x

​

−4

+6)

​

​

in the horizontal addition (above), you may have noticed that running the negative through the parentheses changed the sign on each and every term inside those parentheses. the shortcut when working vertically is to not bother writing in the subtaction sign or the parentheses; instead, write the second polynomial in the second row, and then just flip all the signs in that row, "plus" to "minus" and "minus" to "plus".

i'll change all the signs in the second row (shown in red below), and add down:

\small{ \begin{array}{}x^3& +3x^2& +5x& -4\\ \textcolor{red}{\textbf{--}}\,3x^3& \textcolor{red}{\textbf{+}}\,8x^2& \textcolor{red}{\textbf{+}}\,5x& \textcolor{red}{\textbf{--}}\,6\\ \hline -2x^3& +11x^2& +10x& -10\end{array} }

x

3

–3x

3

−2x

3

​

+3x

2

+8x

2

+11x

2

​

+5x

+5x

+10x

​

−4

–6

−10

​

​

either way, i get the answer:

–2x3 + 11x2 + 10x – 10

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Which do you think is the best measure to use to assess their performance? explain....