Pls answer!!!!
The work of two students is shown for the problem: what is the slope of a line perpendicular to a line that passed through (-21, 12) and ( 16, 11)

Student A
M= 11-12/ 16-(-21) = -1/37
The slope of the perpendicular line is 37

Student B
M= 11-12/ 16-(-21) = -1/37
The slope of the perpendicular line is -37


Part A
Which student has the correct slope of the perpendicular line?

Part B
Explain how the answer to Part A is correct