Answer:
d = 10 sqrt(2)
Step-by-step explanation:
The distance formula is
d = sqrt( (y2-y1) ^2 + ( x2-x1)^2)
d = sqrt( (-1-9) ^2 + ( -4-6)^2)
d = sqrt( (-10) ^2 + ( -10)^2)
d = sqrt( 100+100)
d = sqrt(200)
d = sqrt( 200*2)
d = sqrt(100) sqrt(2)
d = 10 sqrt(2)
