# SOLUTION: determine whether the graphs of the equations are parallel lines, perpendicular lines, or neither. 3x-4y=-5 8x+6y=-5

Algebra ->  Algebra  -> Graphs -> SOLUTION: determine whether the graphs of the equations are parallel lines, perpendicular lines, or neither. 3x-4y=-5 8x+6y=-5      Log On

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 Algebra: Graphs, graphing equations and inequalities Solvers Lessons Answers archive Quiz In Depth

 Question 145400: determine whether the graphs of the equations are parallel lines, perpendicular lines, or neither. 3x-4y=-5 8x+6y=-5Answer by jim_thompson5910(28715)   (Show Source): You can put this solution on YOUR website!To figure out if one line is parallel/perpendicular to another, we must compare the two slopes of the two lines So let's solve for y Start with the first equation Subtract from both sides Rearrange the equation Divide both sides by Break up the fraction Reduce So the equation is now in slope-intercept form () where the slope is and the y-intercept is -------------------- Now let's solve for y Start with the given equation Subtract from both sides Rearrange the equation Divide both sides by Break up the fraction Reduce So the equation is now in slope-intercept form () where the slope is and the y-intercept is ------------------------ From the two equations, we found the first slope was and the second slope was . Notice how the second slope is simply the negative reciprocal of the first slope. So this tells us that the two lines are perpendicular. If you don't believe me, or you need more proof, here's visual proof Graph of (red) and (green)