In this diagram, which equation could prove to be true in order to conclude that the lines are parallel?

b/a = c/d    (first option)

Step-by-step explanation:

Two lines:

f(x) = a*x +b

g(x) = m*x + s

are parallel if m = a, and s ≠ b.

So the lines must have the same slope and different y-intercept.

For the graphed lines is obvious that the y-intercepts are different, so let's look at the slopes.

Remember that if a line passes through the points (x₁, y₁) and (x₂, y₂), then the slope can be written as:

slope = (y₂ - y₁)/(x₂ - x₁)

So now let's look to our lines.

The top one, passes through (-a, 0) and (0, b)

Then its slope is:

a₁ = (b - 0)/(0 - (-a)) = b/a

The bottom line passes through the points (0, -c) and (d, 0)

Then the slope will be:

m₁ = (0 - (-c))/(d - 0) = c/d

Then the lines will be only parallel if the slopes are equal, which means that we must have

b/a = c/d

The correct option is the first one.

answer: 15

step-by-step explanation: