Grade 7 (1) Reference answers to the level test in Chapter 10 of Volume 2 1, 1 ~ 8. BCCADDBA 2，9. 1.56× 10-6 10.2 1 1.0 12。 315. (2n-1) (2n+1) = (2n) 2-116.10/kloc-0 or/kloc. Kloc-0/6y2-9x2)+(3x2+5xy-6xy-65438 (2) Original formula = (m2+N2-2mn) = (m-n) 2 (m+n) 2.19. (1) original formula = ab2, when a =-1, b = 4(2) original formula =1ab (a2+2ab+B2) =1ab (a+b) 2. When a+b = 2 and ab = 2, the original formula = 4.22. 20. The area of the green part is (3a+b) (2a. The green area is 63m2.2 1. (1) a2-6a+8 = a2-6a+9-9+8 = (a-3) 2-1= (a-3-1) (a-3+) (2) from a2+B2+C2. That is, 2a2+ 2b2+ 2c2- 2ab-2bc- 2ac = 0, and we get (a-b) 2+. So a = b = C. Reference answer (b) 1, 1 ~ 8 for the level test in Chapter 10 of the second volume of Grade 7. BCCA·CDBC, two to nine. -x 1 1； a4 10 . m(a-m)(a+m) 1 1.9 . 1× 10-7 12。 0 13.8.2 × 107 14.0 15. 10 B2+7 ab-6 a2 6 5438+06。 2, -3 three, 17. (1) Original formula = 3x (x2+4xy+4y2) = 3x (x+2y) 2; (2) The original formula = (m-1) (m2-4) = (m-1) (m+2).18. (1) original formula = -6m +2, when m. 2(2) original formula = x2- 3, when x =- 1, original formula =-2. 19. ( 1)( 18-2x)； ( 10-x)； (2)( 18-2x)( 10-x)=( 180-38x+2 x2)； (3) 144. IV. 20.( 1)a×b = x2(x- 1)= x3-x2； (2) The answer is not unique. .21coefficient of the first term in the product. (1) is equal to the sum of the constant terms in two factors, and the constant term in the product is equal to the product of the constant terms in two factors; (2) The formula is (x+a) (x+b) = x2+(a+b) x+ab; (3)①a2-a-9 900； ②a2+ a - 9 900。