HI!" please help me with this
A game is played on a cartesian coordinate plane. On each move, a player who is at a point (x,y)moves to a point (-y,3x). After two moves a player who started at (1, -2) will be at
a) (2,3)
b) (-3,6)
c) (6,-3)
d) (3,-6)
e) (1,6)
Thanks for any help on my way.
Start at (x, y) = (1, -2), so x = 1 and y = -2
On the first move the player goes to (-y, 3x). So
we substitute x = 1 and y = -2 in (-y, 3x), and get
(-y, 3x) = ( -(-2), 3(1) ) = (2, 3)
Now for the second move. We are now starting at
(x, y) = (2, 3), so now x = 2 and y = 3
On the second move the player goes to what is now
(-y, 3x). So we substitute x = 2 and y = 3 in (-y, 3x),
and get
(-y, 3x) = ( -(3), 3(2) ) = (-3, 6)
so the answer is choice (b).
Edwin