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quadratic formula: x = (-b +- √(b²-4ac)) / 2a
2 equations, for 2 unknowns (need n equations to solve for n unknowns)
Example: 5x + 2y = 7, 3x - y = 6 Solve by a) graphing both equations and see where they intersect, b) substitution (using one equation set one variable in terms of the other, then substitute into the other equation): y = 3x-6 5x + 2(3x-6) = 7 11x - 12 = 7 c) addition - put all like terms in columns, multiply/divide as needed to get one set of terms to cancel add the terms, solve for the remaining term 5x + 2y = 7 6x - 2y = 12 -------------- 11x = 19, solve for x, then put in to find y
Define x and y in terms of t (time). Arrows on graph represent increasing values of t. Allows you to create functions, using two graphs, from things are not functions for both x and y together (circles, ellipses, x = y², etc)
Eliminating the parameter: substitute for t and define x in terms of y (or vice versa), aka rectangular equation.
https://courses.lumenlearning.com/suny-osalgebratrig/chapter/parametric-equations/