Question

what is the equation of a line that is perpendicular to -x+7y=42 and goes through (-2,-1) in slope intercept form​

Answer 1

• y = -7x - 15

Explanation:

Perpendicular lines have negative reciprocal slopes

Given line

• - x + 7y = 42

In slope-intercept form it is

• - x + 7y = 42
• 7y = x + 42
• y = 1/7x + 6

Perpendicular line has slope - 1/(1/7) = - 7 and its equation is:

• y = - 7x + b

Finding b using the point (-2, -1)

• -1 = -7(-2) + b
• -1 = 14 + b
• b = -1 - 14
• b = -15

So the line is

• y = -7x - 15