y is the vertical axis, x is the horizontal.
X and Y are variables that depend on each other. Normally we treat Y as depending on X.
All the points on the red line have a y-value of 2. This means that the y-axis is the line x=0 and the x-axis is the line y=0.
Every point on this red line, has the same x- and y-values.
The steepness of the lines is called gradient. Guess the gradients of the lines? The green line's gradient is 2, the red line's gradient is 1, and the blue line's gradient is 0.5
The equations give the gradient, since they show by how much y relates to x.
The general formula is y=±mx±c where m is the gradient and c is the y-intercept..Negative gradients slope downwards.