The points 3, 9 and -3,-9 are plotted on the coordinate plane with the equation y=a*x. What is the value of a?

  3

Step-by-step explanation:

The value of "a" can be found by dividing the equation by x, then substituting values from either coordinate pair:

  a = y/x = 9/3 = 3

The value of "a" is 3.

step-by-step explanation:

hans did not square the 40-unit side; he merely multiplied it by 2.   incorrect.

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