Parallel and perpendicular lines

Question

What is the equation of the line written in slope-intercept form that passes through the

point (-1, -6) and is perpendicular to the line y + 6 = - 1/4 (x - 9)?

Answer 1

y+6 = -1/4(x-9) has slope = -1/4

a perpendicular line has slope = 4, the negative inverse of -1/4

take -1/4,change its sign and flip it upside down to get the negative inverse +4/1 = 4

y+1 = (4)(x+6) in point slope form

y = (4)x + 24 -1

y = (4)x +23 in slope intercept form