To find the area under a slope you need to integrate the equation and subtract the lower bound of the area from the upper bound. For linear equations:
Put the equation into the form y = mx + c.
Write a new line where you add 1 to the order of the x (e.g., x becomes x2, x2.5 becomes x3.5).
Divide m by the new number of the order and put it in front of the new x.
Multiply c by x and add this to the new line.
Solve this new line twice, one where x is the upper bound of the area you wish to find and one where x is the lower bound.
Subtract the lower bound from the upper bound.
Congratulate yourself on your achievement.
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