An airplane descends 1.5 miles to an elevation of 5.25 miles. What was the elevation of the plane before its descent?

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Answer 1 · 2018-03-10T17:55:04

See a solution process below:

First, let's call the starting elevation of the plane: #e#

We can then write an equation representing this problem as:

#e - 1.5"mi" = 5.25"mi"#

Now, add #color(red)(1.5"mi")# to each side of the equation to solve for #e# while keeping the equation balanced:

#e - 1.5"mi" + color(red)(1.5"mi") = 5.25"mi" + color(red)(1.5"mi")#

#e - 0 = 6.75"mi"#

#e = 6.75"mi"#
The plane's starting elevation was 6.75 miles