Perpendicular lines have the slopes which product is - 1: m 1 * m 2 = - 1 First we must transform the first line to the slope-intercept form: x + 2 y = 4 2 y = - x + 4 /:2 y = - 1/2 x + 2 Therefore: m 1 = - 1/2 ( - 1/2 ) * m 2 = - 1 m 2 = ( - 1 ) : ( - 1/2 ) = ( - 1 ) * ( - 2 ) = 2 m = 2 ( this is the slope that we need for our equation ) Then we will charge it to the formula : y = m x + b ( which also passes through the point ( 1. 5 ) ): 5 = 2 * 1 + b 5 = 2 + b b = 5 - 2 b = 3 Answer: y = 2 x + 3
