Question

The function y=−0.25x+0.7 represents the percent y (in decimal form) of battery power remaining x hours after you turn on a laptop computer. Identify the x and y intercepts.

Answer 1

x = (2.8, 0) and y = (0, 0.7).

Explanation:

y = -0.25x + 0.7

The y-intercept is when the value of x = 0:

y = -0.25(0) + 0.7 = 0.7.

Solving for the x intercept ( when y = 0):

0 = -0.25x + 0.7

0.25x = 0.7

x = 2.8 hours.

Answer 2

x-intercept: 2.8 hours

y-intercept: 0.7 . . . . fraction of power remaining

Explanation:

The equation is in slope-intercept form, so the y-intercept can be read directly: 0.7.

To find the x-intercept, set y=0 and solve for x:

0 = -0.25x +0.7

0.25x = 0.7 . . . . . add .25x

x = 2.8 . . . . . . . . . multiply by 4 (that is, the reciprocal of 0.25)

The x-intercept is 2.8; the y-intercept is 0.7.