In the equation of a straight line (when the equation is written as "y = mx + b"), the slope is the number "m" that is multiplied on the x, and b is the y-intercept (that is, the point where the line crosses the vertical y-axis). This useful form of the line equation is sensibly named as the "slope-intercept form".The coordinates of every point on the line will solve the equation if you substitute them in the equation for x and y.
The slope m of this line shows its steepness, or slant - It can be calculated like this:
m = change in y-value /change in x-value
The equation of any straight line, called a linear equation, can be written as: y = mx + b ....
3pm to 7pm is 4 hours. 4 hours times 2 degrees dropped every hour is 8 degrees total dropped within those 4 hours. The previous temperature of 4 degrees at 3pm minus the 8 degres dropped is -4.