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numbers and algebraic expressions
logic, sets, intervals
absolute value
function and its properties
linear function
quadratic function
polynomials
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exponential function
logarithm
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derivative and integral of functions
trigonometry
plane geometry
analytic geometry
solid geometry
combinatorics
probability
elements of statistics
kropki game

The image of point A = (x,y) under reflection over $x$ axis is A' = (x,-y). The image of point A = (x,y) under reflection over y axis is A' = (-x,y). Examples. Point. Over x axis. Over y axis.