Question

use the equation of the trend line to predict the cost of the electricity bill after 15 days. y = 3x + 5

Explanation:

Step1: Substitute \(x = 15\) into the equation

Given the equation \(y=3x + 5\), when \(x = 15\), we have \(y=3\times15+5\).

Step2: Calculate the value of \(y\)

First, calculate \(3\times15=45\). Then, \(y = 45+5\).

Answer:

\(50\)