SOLUTION: write an equation for each line. Then Graph thr line through (-3,-1) and perpendicular to {{{y=-(2/5)x-4}}}

Algebra ->  Linear-equations -> SOLUTION: write an equation for each line. Then Graph thr line through (-3,-1) and perpendicular to {{{y=-(2/5)x-4}}}      Log On


   

Question 51217This question is from textbook Prentice Hall Mathematics Algebra 2
: write an equation for each line. Then Graph thr line
through (-3,-1) and perpendicular to y=-%282%2F5%29x-4 This question is from textbook Prentice Hall Mathematics Algebra 2

Answer by rchill(405) About Me  (Show Source):
You can put this solution on YOUR website!
We know the slope of the first line is -%282%2F5%29 because its equation is in the form y=mx+b. By definition, the slopes of two perpendicular lines are negative reciprocals of each other. So the negative reciprocal of -2%2F5 becomes 5%2F2, which is the slope to the perpendicular line. We now have the slope and a point (-3,-1) for the perpendicular line, so we can compute it via substitution into y=mx%2Bb, thusly: -1=%285%2F2%29%2A%28-3%29%2Bb. This reduces to -1=-15%2F2%2Bb. Now we add 15%2F2 to both sides to produce 13%2F2=b. That means the equation for the perpendicular line is y=%285%2F2%29x%2B13%2F2.
graph%28300%2C300%2C-12%2C1%2C-6%2C8%2C%28-2%2F5%29x-4%2C5x%2F2%2B13%2F2%29