Question

Equations must be written in the following format (using the number 20 as an example): Addition x + 20 = y; Subtraction x - 20 = y; Multiplication 20x=y; Division x/20=y

Answer 1

In the graph we can find two points, lets select:

(2, 15) and (4, 30)

Those are the first two points.

Now, for two pairs (x1, y1) (x2, y2)

The slope of the linear equation y = s*x + b that passes trough those points is:

s = (y2 - y1)/(x2 - x1)

So the slope for our equation is

s = (30 - 15)/(4 - 2) = 15/2

then our linear equation is

y = (15/2)*x + b

now we can find b by imposing that when x = 2, y must be 15 (for the first point we selected)

15 = (15/2)*2 + b = 15 + b

b = 15 - 15 = 0

then our equation is:

y = (15/2)*x

Where we used a division and a multiplication.