I. BBADCA

Two. y = 7-2x/5； 2 ; -Four, one, three; ≠-6,=2 ; y= 18-2x，4.5 & ltx & lt9 ; h=0.5+0.4n，4.5

Three. 13.( 1) Omit (2) (2,0)14. Not in 15. (1) Y = 424x+3 18 (2) when 4 ≤ X. 6: a when x=6: both companies are 6.

I.db

(-3,-1) or (-1,1); three

III.5.y = 4x-3 6。 (1)0: 32 km/h (2)

23rd edition:

I. BDACAC

II.9; 9 trees; 95 points; Class b; Mode, average and median; X pull +2

Three. 13. (1)-1(2)-114. (1) Mode:14 years old, with an average of14 years old.

I. Canada

II.3 or 4 or 5; 96

III.5. (1)1,1,2,3,4,5,3,1; 1.6 (2) 1.2, 1.3 (3) median, because the average will be affected by extreme data, the median can reflect the middle level of this group of data. 6.( 1) Average: 6.8t, mode: 6.5t, median: 6.5t (2)35 households.

26th edition:

I. BDCDBA

II.02.0 ; (4,-2); 6 ; 3a-5； 6 ; x=-4，y =-2； 40,70 or 100.

Three. 15. (1)-1(2) x = 4 or -2 16. (1) sketch, (-6,2) (2) 2017. Sketch. In 2006

y=2x-3 (3)0.75

19.( 1) A: 7， 1 B: 7.5，3 (2) B，B，B。

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