Question

A student arrives at school without their phone fully charged. The chart below shows thenumber of minutes verses the percent of the remaining battery. Write an equation in slopeintercept form that models this situation.

Answer 1

The equation of the line is given by:

$y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)_{}$

plugging the values of the first two rows we have that:

$\begin{gathered} y-55=\frac{52-55}{16-4}(x-4) \\ y-55=\frac{-3}{12}(x-4) \\ y-55=-\frac{1}{4}(x-4) \\ y-55=-\frac{1}{4}x+1 \\ y=-\frac{1}{4}x+56 \end{gathered}$

Therefore the equation is:

$y=-\frac{1}{4}x+56$