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Questions in mathematics

[Done] Is -5 + (-3) equal to -3 + (-5)?

[Done] Select all the correct answers. Which expressions are equivalent to the given expression? [tex]$\sqrt{40}$[/tex] [tex]$5 \sqrt{8}$[/tex] [tex]$2 \sqrt{10}$[/tex] [tex]$4 \sqrt{10}$[/tex] [tex]$160^{\frac{1}{2}}$[/tex] [tex]$40^{\frac{1}{2}}$[/tex]

[Done] Which pair of complex numbers has a real-number product? (1+2 i)(8 i) (1+2 i)(2-5 i) (1+2 i)(1-2 i) (1+2 i)(4 i)

[Done] Describe the error made in subtracting the two rational expressions shown: [tex]\begin{array}{l} \frac{1}{x-2}-\frac{1}{x+1} \ =\frac{x+1}{(x-2)(x+1)}-\frac{x-2}{(x-2)(x+1)} \ =\frac{-1}{(x-2)(x+1)} \end{array}[/tex]

[Done] Suppose a survey of adults and teens (ages 12-17) in a certain country was conducted to determine the number of texts sent in a single day. (a) Construct a relative frequency distribution for adults. (b) Construct a relative frequency distribution for teens. (c) Construct a side-by-side relative frequency bar graph. (d) Compare the texting habits of adults and teens. \begin{tabular}{lcc} \hline Number of Texts & Adults & Teens \\ \hline None & 164 & 16 \\ \hline $1-10$ & 974 & 147 \\ \hline $11-20$ & 257 & 70 \\ \hline $21-50$ & 254 & 122 \\ \hline $51-100$ & 135 & 115 \\ \hline $100+$ & 147 & 189 \\ \hline \end{tabular} (a) Complete the table below. \begin{tabular}{l|l|l} \hline Number of Texts & \multicolumn{2}{c}{ Adults } \\ \hline None & & \\ \hline $1-10$ & & \\ \hline $11-20$ & & \\ \hline $21-50$ & & \\ \hline $51-100$ & & \\ \hline $100+$ & & \\ \hline \end{tabular} (Round to three decimal places as needed.)

[Done] The table shows the number of calories in four meals and the cost of each meal. Cost of Meal and Number of Calories | Number of calories in the meal | Cost of the meal | | :----------------------------- | :--------------- | | 550 | $12 | | 1,250 | $11 | | 780 | $13 | | 650 | $10 | Which best describes the strength of the model? A. a weak positive correlation B. a strong positive correlation C. a weak negative correlation D. a strong negative correlation

[Done] $6 \sqrt{11}+\sqrt[3]{4.4}-1.83^5$

[Done] What are the values of $a_1$ and $r$ of the geometric series? $2-2+2-2+2$ A. $a_1=2$ and $r=-2$ B. $a_1=-2$ and $r=2$ C. $a_1=-1$ and $r=2$ D. $a_1=2$ and $r=-1$

[Done] Subtract. [tex]$\frac{b+7}{3 b}-\frac{9 b+7}{4 b}$[/tex]

[Done] Multiply. $(9 x-2)(-4 x-3)$