The linear equation that is perpendicular to the line x+3y=21 is:
y = 3*x - 6
<h3>How to find the equation of the line?</h3>
A general line in the slope-intercept form is written as:
y = m*x + b
Where m is the slope and b is the y-intercept.
Two linear equations are perpendicular if the product between the two slopes is equal to -1.
Rewriting the given line we can get:
x +3y = 21
3y = 21 - x
y = 21/3 - x/3
y = (-1/3)*x + 21/3
Then the slope is (-1/3), if our line is perpendicular to this one, then:
m*(-1/3) = -1
m = 3
our line is:
y = 3*x + b
To find the value of b, we use the fact that our line passes through (1, - 3)
-3 = 3*1 + b
-3 - 3 = b
-6 = b
The line is y = 3*x - 6
Learn more about linear equations:
brainly.com/question/1884491
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