Sides RS and TU have the same slope, so they are parallel. The slope of side ST is the negative reciprocal of the slopes of sides RS and TU, so side ST is perpendicular to sides RS and TU. Side UR is not parallel or perpendicular to any other side.
Factor 7 x 7 x out of 14 x 2 14 x 2 . 7 x ( 2 x ) − 21 x 7 x 2 x - 21 x Factor 7 x 7 x out of − 21 x - 21 x . 7 x ( 2 x ) + 7 x ( − 3 ) 7 x 2 x + 7 x - 3 Factor 7 x 7 x out of 7 x ( 2 x ) + 7 x ( − 3 ) 7 x 2 x + 7 x - 3 . 7 x ( 2 x − 3 )