Mathematical problems in the first volume of the first day of junior high school

(1) Fill in the blanks

3.3ab-4ab+8ab-7ab+ab=______。

4.7x-(5x-5y)-y=______。

5.23 a3 BC 2- 15 ab2c+8 ABC-24 a3 BC 2-8 ABC = _ _ _ _ _ _。

6.-7x 2+6x+ 13 x2-4x-5x 2 = _ _ _ _ _ _。

7.2y+(-2y+5)-(3y+2)=______。

1 1.(2 x2-3xy+4 y2)+(x2+2xy-3 y2)= _ _ _ _ _ _。

12.2 a-(3a-2 b+2)+(3a-4 b- 1)= _ _ _ _ _ _。

13.-6x2-7x2+ 15x2-2x2=______。

14.2 x-(x+3y)-(-x-y)-(x-y)= _ _ _ _ _ _。

16.2 x+2y-[3x-2(x-y)]= _ _ _ _ _ _。

17.5-( 1-x)- 1-(x- 1)= _ _ _ _ _ _。

18.()+(4xy+7x2-y2)= 10x2-xy。

19.(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3。

2 1. Given A=x3-2x2+x-4 and B=2x3-5x+3, calculate a+b = _ _ _ _.

22. given A=x3-2x2+x-4 and B=2x3-5x+3, calculate a-b = _ _ _ _.

23. If a=-0.2 and b=0.5, the value of the algebraic expression -(|a2b|-|ab2|) is _ _ _ _ _.

25. If a polynomial subtracts 3m4-m3-2m+5 to get -2m4-3m3-2m2- 1, then this polynomial is equal to _ _ _ _.

26.-(2 x2-y2)-[2 y2-(x2+2xy)]= _ _ _ _ _ _。

27. If -3a3b2 and 5ax- 1by+2 are similar terms, then x = _ _ _ _ _, and y = _ _ _ _ _.

28.(-y+6+3 y4-y3)-(2 y2-3 y3+y4-7)= _ _ _ _ _ _。

29. The result of simplifying the algebraic expression 4x2-[7x2-5x-3( 1-2x+x2)] is _ _ _ _.

30.2 a-B2+c-D3 = 2a+()-D3 = 2a-D3-()= c-()。

3 1.3a-(2a-3b)+3(a-2b)-b = _ _ _ _ _ _。

32. The simplified algebraic expression x-[y-2x-(x+y)] is equal to _ _ _ _.

33.[5a 2+()a-7]+[()a2-4a+()]= a2+2a+ 1。

34.3x-[y-(2x+y)]=______。

35.Simplify | 1-x+y |-x-y | (where x < 0, y > 0) equals _ _ _ _.

36. It is known that x≤y, x+y-| x+y-| x-y | = _ _ _ _ _

37. Given x < 0 and y < 0, simplify | x+y |-| 5-x-y | = _ _ _.

38.4a2n-an-(3an-2a2n)=______。

39. If you add -3x2y+2x2-3xy-4 to a polynomial, you get.

2x2y+3xy2-x2+2xy，

Then this polynomial is _ _ _ _.

40.-5xm-xm-(-7xm)+(-3xm)=______。

4 1. When a=- 1 and b=-2,

[a-(b-c)]-[-b-(-c-a)]=______。

43. When a=- 1, b= 1 and c=- 1,

-[b-2(-5a)]-(-3b+5c)=______。

44.-2(3x+z)-(-6x)+(-5y+3z)=______。

45.-5an-an+ 1-(-7an+ 1)+(-3an)= _ _ _ _ _ _。

46.3 a-(2a-4 b-6c)+3(-2c+2b)= _ _ _ _ _ _。

48.9 a2+[7 a2-2a-(-a2+3a)]= _ _ _ _ _ _。

50. When 2y-x=5, 5 (x-2y) 2-3 (-x+2y)-100 = _ _ _.

(2) Choose

[ ]

A.2

B.-2;

C.- 10;

D.-6.

52. In the following categories, the calculation result is -7x-5x2+6x3 [].

a . 3x-(5 x2+6 x3- 10x)；

b . 3x-(5 x2+6 x3+ 10x)；

c . 3x-(5 x2-6 x3+ 10x)；

D.3x-(5x2-6x3- 10x)。

53. Combine (-x-y)+3(x+y)-5(x+y) into the same category [].

A.(x-y)-2(x+y)；

B.-3(x+y)；

C.(-x-y)-2(x+y)；

D.3(x+y)。

54.2a-[3b-5a-(2a-7b)] equals []

A.-7a+ 10b；

b . 5a+4b；

C.-a-4b；

D.9a- 10b。

55. The algebraic expression that minus -3m equals 5m2-3m-5 is [].

a . 5(m2- 1)；

b . 5m 2-6m-5；

c . 5(m2+ 1)；

D.-(5m2+6m-5)。

56. The similar terms in the polynomial 2ab-9a2-5ab-4a2 are combined together respectively, which should be [].

A.(9 a2-4a 2)+(-2 ab-5ab)；

B.(9 a2+4a 2)-(2ab-5ab)；

C.(9 a2-4a 2)-(2ab+5ab)；

D.(9a2-4a2)+(2ab-5ab)。

57. When a=2 and b= 1, -a2b+3ba2-(-2a2b) equals [].

A.20

B.24

C.0

D. 16。

The correct choice is []

A. there is no similar project;

B.(2) and (4) are similar projects;

C.(2) and (5) are similar projects;

D.(2) and (4) are not a category.

59. If both A and B are quintic polynomials, A-B must be [].

A. decagonal polynomial;

B. zeroth polynomial;

C. Polynomials with a degree not higher than five;

D. polynomial with degree less than five.

60.-{[-(x+y)]}+{-[(x+y)]} equals []

A.0

B.-2y；

c . x+y；

D.-2x-2y。

6 1. If A=3x2-5x+2 and B=3x2-5x+6, the sizes of A and B are

[ ]

A.a > B；

B.a = B；

C.a < B；

D. not sure.

62. When m=- 1, -2m2-[-4m2+(-m2)] equals [].

A.-7;

B.3

c . 1；

D2。

63. When m=2 and n= 1, the polynomial -m-[-(2m-3n)]+[-(-3m)-4n] is equal to [].

a . 1；

B.9

C.3

D.5

[ ]

65.-5an-an-(-7an)+(-3an) equals []

A.- 16an；

B.- 16;

C.-2an；

D.-2.

66.(5a-3b)-3 (a2-2b) is equal to []

a . 3 a2+5a+3b；

b . 2 a2+3b；

c . 2 a3-B2；

D.-3a2+5a-5b。

67.X3-5x2-4x+9 equals []

A.(x3-5 x2)-(-4x+9)；

b . x3-5x 2-(4x+9)；

C.-(-x3+5 x2)-(4x-9)；

D.x3+9-(5x2-4x)。

[ ]

The result of 69.4x2y-5xy2 should be []

A.-x2y；

B.- 1;

C.-x2y 2；

D. None of the above answers are correct.

(3) simplification

70.(4x2-8x+5)-(x3+3x2-6x+2)。

72.(0.3x 3-x2y+xy2-y3)-(-0.5x 3-x2y+0.3 xy2)。

73.-{2a2b-[3abc-(4ab2-a2b)]}。

74.(5a2b+3a2b 2-ab2)-(-2ab 2+3a2b 2+a2b)。

75.(x2-2 y2-z2)-(-y2+3 x2-z2)+(5x 2-y2+2z 2)。

76.(3 a6-a4+2 a5-4 a3- 1)-(2-a+a3-a5-a4)。

77.(4a-2b-c)-5a-[8b-2c-(a+b)]。

78.(2m-3n)-(3m-2n)+(5n+m)。

79.(3 a2-4 ab-5 B2)-(2 B2-5a 2+2ab)-(-6ab)。

80.xy-(2xy-3z)+(3xy-4z)。

8 1.(-3x 3+2 x2-5x+ 1)-(5-6x-x2+x3)。

83.3x-(2x-4y-6x)+3(-2z+2y)。

84.(-x2+4+3x4-x3)-(x2+2x-x4-5)。

85. If A=5a2-2ab+3b2 and B=-2b2+3ab-a2, calculate a+b. 。

86. It is known that A=3a2-5a- 12, B=2a2+3a-4, and find 2 (a-b).

87.2m-{-3n+[-4m-(3m-n)]}。

88.5m2n+(-2m2n)+2mn2-(+m2n)。

89.4(x-y+z)-2(x+y-z)-3(-x-y-z)。

90.2(x2-2xy+y2-3)+(-x2+y2)-(x2+2xy+y2)。

92.2(a2-a b-B2)-3(4a-2b)+2(7 a2-4a b+B2)。

94.4x-2(x-3)-3[x-3(4-2x)+8]。

(4) Simplify the following categories before evaluating.

97. Given a+b=2 and a-b=- 1, find the value of 3(a+b)2(a-b)2-5(a+b)2×(a-b)2.

98. It is known that A=a2+2b2-3c2, B=-b2-2c2+3a2, C=c2+2a2-3b2, and find (A-B)+C. 。

99.Find (3x2y-2x2y)-(xy2-2x2y), where x=- 1 and y = 2.

10 1. Given |x+ 1|+(y-2)2=0, find the value of algebraic expression 5(2x-y)-3(x-4y).

106. when P=a2+2ab+b2 and Q=a2-2ab-b2, find p-[q-2p-(p-q)].

107. Find the value of 2x2-{-3x+5+[4x2-(3x2-x=-3. 1)], where x =-3.

1 10. When x=-2, y=- 1 and z=3, find the value of 5XYZ-{2x2y-[3xXYZ-(4xy2-x2y)]}.

1 13. Given A=x3-5x2 and B=x2-6x+3, find a-3 (-2b).

(5) Comprehensive exercises

1 15. Remove the brackets: {-[-(a+b)]}-{-[-(a-b)]}.

1 16. Delete the brackets: -[-(-x)-y]-[+(-y)-(+x)].

1 17. Given A=x3+6x-9 and B=-x3-2x2+4x-6, calculate 2A-3B, and put the result in brackets with "-"in front.

1 18. Calculate the following formula and put the result in brackets with "-"in front:

(-7 y2)+(-4y)-(-y2)-(+5y)+(-8 y2)+(+3y)。

1 19. Remove the brackets, merge similar items, and arrange the results according to the ascending power of x, and put the last three items in brackets with "-":

120. Without changing the value of the following formula, change the symbol before each bracket to the opposite symbol: (x3+3x2)-(3x2y-7xy)+(2y3-3y2).

12 1. Put the cubic term of polynomial 4x2y-2xy2+4xy+6-x2y2+x3-y2 in brackets with "-"in front, the quadratic term in brackets with "+"in front, and the quartic term and constant term in brackets with "-"in front.

122. Remove the brackets of the following polynomials, combine similar terms, put them in brackets with "-"in front, and then find the value of 2x-2[3x-(5x2-2x+ 1)]-4x2, where x =- 1.

123. Merge similar projects:

7x- 1.3z-4.7-3.2x-y+2. 1z+5-0. 1y。

124. Merge similar items: 5m2n+5mn2-Mn+3m2n-6mn2-8mn.

126. Remove brackets and merge similar items:

( 1)(m+ 1)-(-n+m)；

(2)4m-[5m-(2m- 1)]。

127. Simplified: 2x2-{-3x-[4x2-(3x2-x)+(x-x2)]}.

128. Simplification:-(7x-y-2z)-{[4x-(x-y-z)-3x+z]-x}.

129. Calculation: (+3a)+(-5a)+(-7a)+(-31a)-(+4a)-(-8a).

130. Simplification: a3-(a2-a)+(a2-a+1)-(1-a4+a3).

13 1. Combine the similar items of x2-8x+2x3- 13x2-2x-2x3+3 and evaluate them, where x =-4.

132. Fill in the appropriate items in brackets: [()-9y+()]+2y2+3y-4 =11y2-()+13.