I have 21 students and each picture takes 3 minutes and each class picture takes 10 minutes

It would take 73 minutes in total.

Step-by-step explanation:

21 students x 3 minutes = 63 minutes

63 + 10 = 73

I hope this is what you were asking :)

step-by-step explanation:

b

step-by-step explanation:

the equation of a line in point- slope form is

y - b = m(x - a)

where m is the slope and (a, b) a point on the line

calculate m using the slope formula

m = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (0, 4) and (x₂, y₂ ) = (3, - 5) ← 2 points on the line

m = = = - 3

with m = - 3 and (a, b) = (3, - 5), then

y - (- 5) = - 3(x - 3), that is

y + 5 = - 3(x - 3) → b