Question

1.Is the line contains the points P1(-1,2)and P2(3,4) perpendicular to the line that contains the points Q1(-1,3)and Q2(-4,1)?
2.a line given two points P1(4,5),P2(-4,3)

Answer 1

figure the slopes of each line.
PI,P2 slope=deltay/deltax=4-2/3+1=1/2
P3,P3 slope=3-1/4+4=-1/4
the slopes are not negative reciprocals, they are not perpendicular.