问题
解答题
已知:x:y:z=2:3:4,求: (1)
(2)
(3)
|
答案
(1)∵x:y:z=2:3:4,
∴设x=2a,y=3a,z=4a,
∴
=x+2y y
=2a+6a 3a
;8 3
(2)
=3x 2x+3y-5z
=-3×2a 2×2a+3×3a-5×4a
;6 7
(3)
=x+2y+3z 3x-2y-z
=-5.2a+2×3a+3×4a 6a-6a-4a
已知:x:y:z=2:3:4,求: (1)
(2)
(3)
|
(1)∵x:y:z=2:3:4,
∴设x=2a,y=3a,z=4a,
∴
=x+2y y
=2a+6a 3a
;8 3
(2)
=3x 2x+3y-5z
=-3×2a 2×2a+3×3a-5×4a
;6 7
(3)
=x+2y+3z 3x-2y-z
=-5.2a+2×3a+3×4a 6a-6a-4a