求×,y+已知a=(-3,1)+b=(5,-3)+实数xa+yb=(2,-7)+则x,y等于多少
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a=(-3,1),b=(5,-3)
xa+yb=(2,-7)
x(-3,1)+y(5,-3)=(2,-7)
(-3x+5y, x-3y) =(2,-7)
-3x+5y=2 (1)
x-3y=-7 (2)
3(2)+(1)
-4y=-19
y=19/4
from (2)
x-3y=-3
x-57/4=3
x=69/4
(x,y)=(69/4,19/4)
xa+yb=(2,-7)
x(-3,1)+y(5,-3)=(2,-7)
(-3x+5y, x-3y) =(2,-7)
-3x+5y=2 (1)
x-3y=-7 (2)
3(2)+(1)
-4y=-19
y=19/4
from (2)
x-3y=-3
x-57/4=3
x=69/4
(x,y)=(69/4,19/4)
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