Calculus
posted by Jake .
which pair of lines are perpendicular?
a) 2x + 3y  7=0, 3x  2y + 2=0
b) 2x  3y + 2=0, 5x  7y + 2=0
c) 4x + y  3=0, x + 4y=0
d) 5x + y + 1=0, 5x + y + 1=0
Please explain. I know we have to use the dot product :3

for any ax + by + c = 0 , the direction vector of the normal is (a,b)
If the normals are perpendicular, then obviously the line are perpendicular, so ...
a)
normal to first line is (2,3)
normal to 2nd line is (3,2)
dot product = 6  6 ≠ 0
so the lines are NOT perpendicular.
do the others the same way.
If you get a dot product of zero , they are perpendicular.
Respond to this Question
Similar Questions

PLease check math
1)Find an eauation of the line containing the given pair of points. (2,1) and (6,3) MY ANSWEAR: Y=(1/2)X 2)Decide whether the pair of lines is perpendicular, parallel, or neither. What is the slope of 4x+2y=3 4x+2y=4 MY ANSWEAR: … 
algebra
Is the following pair of lines paralle or perpendicular? 
geometry
Martin drew a pair of perpendicular lines and a pair of parallel lines. Which of these statements best compares the pairs of perpendicular and parallel lines? 
Geometry
If two non parallel lines are perpendicular to two other straight lines , each to each . Show that the acute angle between the first pair of lines is equal to the acute angle between the second pair of lines. 
math help please
Tell whether the lines for each pair of equations are parallel, perpendicular, or neither. x + 5y = –20 y = –7/8x – 1 32x – 28y = –36 parallel perpendicular neither I think it's perpendicular  asked this question earlier … 
math
Find the slope of the lines that are (a) parallel lines (b) perpendicular lines to the lines passing through the pair of points (3, 4)(2,1) 
math
Find the slope of the lines that are (a) parallel lines (b) perpendicular lines to the lines passing through the pair of points (3, 4)(2,1) 
math help`
is it true that no matter what the ordered pair is that parallel lines have the same slope and perpendicular lines some is always 1 
Algebra
Correct me if I'm wrong please 1. Tell whether the lines for each pair of equations are parallel, perpendicular, or neither. y = –2x + 4 –5x + 10y = 5 (1 point) A.parallel B.perpendicular * C.neither 2. Tell whether the lines for … 
Math ASAP
1. tell whether the lines of each pair of equations are parallel or perpendicular or neither Y=3x+7 2x+6y=3 *Perpendicular 2. tell whether the lines of each pair of equations are parallel or perpendicular or neither Y=1/4x+10 2x+8y=6