Line t passes through points (3, 11) and (8, 4). Line u passes through points (1, 4) and (8, 9). Are line t and line u parallel or perpendicular?

The lines t and u are perpendicular.

Step-by-step explanation:

m=(y2-y1)/(x2-x1)

m=(4-11)/(8-3)

m=-7/5

m=(y2-y1)/(x2-x1)

m=(9-4)/(8-1)

m=5/7

Perpendicular lines have negative reciprocal slopes.

for this case we must apply distributive property to the following expression:

the distributive property states that:

then, when applying the property we have to multiply the -2 for each term within the parenthesis: