$30$ Chapter $2$ Variables and Their Measurement

$7.$ For the data of Exercise $6,$ consider the sum ${\displaystyle \underset{?}{\overset{?}{}}}(\frac{2(x-Y{)}^2}{x+Y}).$

$($a$)$ How many columns are required for this computation, following the suggestions of Box $2\mathrm{.}3?$ What are their headings?

$($b$)$ Compute the sum.

$8.$ For the data of Exercise $6,$ demonstrate each expression.

$($a$)x^2(x{)}^2$

$($b$)(x+5)x+5$

$($c$)(x+5{)}^2(x+5{)}^2$

$($d$)xYxY$

$9.($a$)$ For the data of Exercise $6,$ how many decimal places should you use in reporting the value of $\frac{x}{3}$ as a final answer?

$($b$)$ What is that value? Be sure to round correctly.

$10.$ Round each value to two decimal places.

$($a$)14\mathrm{.}637$

$($f$)3\mathrm{.}315$

$($b$)-14\mathrm{.}637$

$($g$)3\mathrm{.}325$

$($c$)2\mathrm{.}152$

$($h$)3\mathrm{.}335$

$($d$)3\mathrm{.}40500$

$($i$)27\mathrm{.}43475$

$($h$)$ For these data, does $(x-3)=x-3?$

$($i$)$ Create a column headed $"x^2-9"$ and compute $(x^2-9)$

$12.$ For the data of 'Exercise $11,$ consider the sum ${\displaystyle \underset{?}{\overset{?}{}}}(\frac{(x_i-3)(2x_i+4)}{2})$

$($a$)$ How many columns are required for this computation, following the suggestions of Box $2\mathrm{.}3?$ What are their headings?

$($b$)$ Compute the sum

$13.$ Consider the data in the accompanying table.

$($a$)$ Find $x_4-Y_4.$

$($b$)$ Compute $xY.$

$\backslash$table$[[x,Y$