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X
- GIVEN THE FUNCTION OF 2 VARIABLES,
WE WANT TO DETERMINE EACH FUNCTION VALUE.
SO FOR F OF 3,1 WE'LL SUBSTITUTE 3 FOR X AND 1 FOR Y.
SO FOR 90X WE'D HAVE 90 X 3 + 100 Y
WOULD BE 100 X 1 - 2 X "X" SQUARED.
THAT WOULD BE 2 X 3 SQUARED - 5 X Y SQUARED
WOULD BE 5 X 1 SQUARED.
AND THEN - "X" X Y WOULD BE - 3 X 1.
AND NOW WE'LL GO AHEAD AND SIMPLIFY.
90 X 3 IS 270 + THIS WOULD BE 100.
HERE 3 SQUARED IS 9, 9 X 2 IS 18
SO WE'D HAVE - 18, 1 SQUARED IS 1 X 5 IS 5,
SO WE HAVE - 5 AND THEN - 3.
SO WE HAVE 270 + 100 - 18 - 5 - 3 WHAT IS = 344.
SO F OF 3,1 = 344.
NEXT WE HAVE F OF -2,3, SO NOW WE'LL SUBSTITUTE -2 FOR X
AND SUBSTITUTE 3 FOR Y.
SO FOR 90X WE'D HAVE 90 X -2 + 100 Y WOULD BE 100 X 3 - 2
TIMES X SQUARED,
THAT'D - 2 X -2 SQUARED - 5 X Y SQUARE
WOULD BE - FIVE TIMES 3 SQUARED.
AND THEN FINALLY - "X" TIMES Y WOULD BE - NEGATIVE 2 X 3.
SO HERE WE'D HAVE -180 + 300.
NEGATIVE 2 SQUARED IS FOUR, 4 TIMES 2 IS EIGHT,
SO HAVE - EIGHT AND HERE WE HAVE 3 SQUARED,
THAT'S 9 TIMES 5 THAT'S - 45
AND THEN HERE WE HAVE - -6 WHICH WOULD BECOME + 6.
SO NEGATIVE 180 + 300 - 8 - 45 + 6 = 73.
SO F OF -2,3 = 73.