Question

a hot air ballon was at 2,180 feet. it decended at 120 feet per minute for 9 minutes. what is the balloons new height?

Answer 1

Answer:

The balloons new height is $1,100\ ft$

Step-by-step explanation:

Let

x ----> the number of minutes

y ----> the height of a hot air balloon in feet

we know that

The linear equation in slope intercept form is equal to

$y=mx+b$

where

m is the slope or unit rate

b is the y-intercept or initial value

In this problem we have

The slope is equal to

$m=-120\ ft\ per\ minute$ ---> is negative because is a decreasing function

The y-intercept is equal to

$b=2,180\ ft$

substitute

$y=-120x+2,180$

For x=9 minutes

substitute in the linear equation

$y=-120(9)+2,180$

$y=1,100\ ft$