Question

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

Explanation:

Step1: Identify the variables

The equation is $y = 3x+5$, where $x$ is the number of days and $y$ is the cost of the electricity bill.

Step2: Substitute the value of x

We want to find the cost when $x = 15$. Substitute $x=15$ into the equation $y = 3x + 5$.
$y=3\times15 + 5$

Step3: Perform the calculation

First, calculate $3\times15=45$. Then, $y=45 + 5=50$.

Answer:

50