Chapter 8.9, Problem 2CYU

(a)

To determine

Write equation of the graph.

Answer to Problem 2CYU

Equation of graph is $y=0.5x+0.7$

Explanation of Solution

Given data:

Graph of sales of book v/s year

Formula used:

Slope intercept form:

  $y=mx+C$

Calculation:

a. Equation for given graph :

Slope of graph at (4,2.3)and(5,2.8)

  $\begin{array}{l}m=\tan \theta =\frac{y_2-y_1}{x_2-x_1}\\ m=\frac{2.8-2.3}{5-4}\\ m=\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.\end{array}$

Y intercept =C=0.7

So equation of graph is

  $\begin{array}{l}y=mx+C\\ y=0.5x+0.7\end{array}$

Conclusion:

Equation of graph is $y=0.5x+0.7$

(b)

To determine

Predict the sales of book in 2013.

Answer to Problem 2CYU

The sales of book in 2013 is 1007.2 $billions

Explanation of Solution

Given data:

Graph of sales of book v/s year

  $y=0.5x+0.7$

Formula used:

Slope intercept form:

  $y=mx+C$

Calculation:

Sales of in 2013 is

  $\begin{array}{l}y=mx+C\\ y=0.5x+0.7\\ y=0.5(2013)+0.7\\ y=1007.2\end{array}$

The sales of book in 2013 is 1007.2 $billions

Conclusion:

The sales of book in 2013 is 1007.2 $billions