It is urgent to solve mathematical polynomial math problems from the 50 th day of the first day of junior high school! ! ! ! ! ! ! ! ! ! !

2.2 Algebraic expression addition and subtraction (1)

1. Two of the following groups are ().

A.a2b and-6ab2b. -X3y and 2YX3C.2r and 2RD.35 and 53.

2. The following calculation is correct ().

a . 3 a2-2 a2 = 1 b . 5-2 x3 = 3x 3 c . 3 x2+2 x3 = 5x 5d . a3+a3 = 2 a3

3. The polynomial minus -4x equals 3x2-2x- 1 is ().

a . 3 x2-6x- 1 b . 5 x2- 1 c . 3 x2+2x- 1d . 3 x2+6x- 1

4. If both A and B are polynomials of degree 6, then A+B must be ().

A. 12 polynomial b.6 polynomial

C. algebraic expression with degree not higher than 6 d. Polynomial with degree not less than 6

5. The value of polynomial-3x2y-10x3+3x3+6x3y+3x2y-6x3y+7x3 is ().

A. it has nothing to do with x and y. b has nothing to do with X. C, Y. D, x and y.

6. If the polynomial 3x3-2x2+x+│ k │ x2-5 does not contain x2 term, then the value of k is ().

A.2b-2c . 2d . 0

7. If 2x2ym and-3xny3 are similar terms, then m+n _ _ _ _ _.

8. Calculation: (1) 3x-5x = _ _ _ _ _ _; (2) (Hebei, 2008) The result of calculating a2+3a2 is _ _ _ _ _.

9. Merge similar items:-AB2+AB2-AB2 = _ _ _ _ _.

10. The middle of five consecutive even numbers is n, and the sum of these five numbers is _ _ _ _ _ _.

1 1. If m is a constant and the polynomial mxy+2x-3y- 1-4xy is a trinomial, the value of m2-m+2 is _ _ _ _ _.

12. if the monomials-a2xbm and Anby- 1 can be combined into a2b4, then XY-Mn = _ _ _ _ _ _

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13. Merge similar projects in the following categories:

( 1)-0.8 a2b-6ab-3.2 a2b+5ab+a2b；

(2)5(a-b)2-3(a-b)2-7(a-b)-(a-b)2+7(a-b)。

14. Simplify before evaluating:

(1) 5a2-4a2+a-9a-3a2-4+4a, where a =-;

(2) 5ab-a2b+a2b-ab-a2b-5, where a= 1 and b =-2;

(3) 2a2-3ab+b2-a2+ab-2b2, where a2-b2 = 2 and ab =-3.

15. The polynomial 6m-2n+2 4nxy+2x+2xy-x2+y+4 about x and y contains no quadratic term. Find the value of 6m-2n+2.

16. Each teapot sold in the store costs 20 yuan, and each teacup costs 5 yuan. The store has formulated two preferential measures: (1) buying teapots and sending teacups; (2) Pay 92% of the total price. A customer needs to buy 4 teapots and X teacups (x≥4), and the payment amount is Y (Yuan). Try to write the relationship between Y and X for the two preferential ways, and study which one is more economical when customers buy the same number of tea cups?

Reference answer:

1.A 2。 D 3。 A 4。 C 5。 A six. A 7.5 8. ( 1)-2x (2)4a2 9。 -ab2

10.5n÷ 1 1.6 12。 -3 13.( 1)-3a2b-ab (2)(a-b)2

14.( 1) Original formula =-2a2-5a with a value of 2 (2) Original formula = ab-5a2b-5 with a value of.

(3) The original formula = a2-b2-2ab, with a value of 8.

2.2 Addition and subtraction of algebraic expressions (2)

1. The result of simplifying m+n-(m-n) is ().

A.2m B.-2m C.2n D.-2n

2.2x- 1 The polynomial equal to 3x2-x-3 is ().

a . 3 x2+x-4 b . 3 x2-3x-4 c . 3 x2-3x-2d . 3 x2+x+2

3. When Xiao Ming was reviewing his class notes, he found a problem: (-x2+3xy-y2)-(-x2+4xy _ _ _ _) =-x2-xy+y2, and the space was stained with a pen, so this item in the space is ().

A.y2 B.3y2 C.-y2 D.-3y2

4. The sum of a number and 1 is equal to 3 times of A, and this number is equal to ().

a . a-3 b . 3a- 1 c . 9a- 1d . 9a-3

5. If the graph is composed of a square and a right triangle, the area of the graph is ().

A.m2+mn B。

6. The value of polynomial (XYZ 2+4yx-1)+(-3xy+Z2yx-3)-(2XYZ 2+xy) ().

A. it has nothing to do with the size of x, y and z. b, it has something to do with the size of x and y, and has nothing to do with the size of Z.

C is related to the size of x, not to the size of y and z, and d is related to the size of x, y and z.

7. Simplification: (1) (2x-4y)+2y = _ _ _ _ _ _; (2)(2xy-y)-(-y+xy)=________。

8. If m =-8, the value of -2m2-[-4m2+(-m) 2] is _ _ _ _ _.

9. If x-2y = 5, then 5-3x+6y = _ _ _ _.

10. If a2+2b2=5, the value of the polynomial (3a2-2ab+b2)-(a2-2ab-3b2) is _ _ _ _ _ _.

1 1. If the circumference of a triangle is 48, the first side is 4a+3b, and the second side is 2a-b less than twice that of the first side, then the third side is _ _ _ _ _ _ _.

12. it is known that y = AX5+Bx3+CX- 1. when x =-2 and y=5, then when x=2, y = _ _ _ _

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13. Simplify before evaluating:

(1) (3a2-AB+7)-(5ab-4a2+7), where a=2 and b =；;

(2) x-2 (x-y2)+3 (-x+y2), where x =-2 and y =-;

(3)-5abc-{2a2b-[3abc-2 (2ab2-a2b)]}, where a =-2, b =- 1, and c = 3.

14. It is proved that the value of the polynomial16+a-{8a-[a-9-3 (1-2a)]} has nothing to do with the value of the letter A. 。

15. A student mistook a polynomial minus X2+6x-6 for addition calculation because of a sign error, and got 2x2-2x+3. What should be the correct result?

16. A farm tool factory spent M yuan on electricity in the first quarter, and the water fee was less than twice that of 40 yuan. In the second quarter, the electricity bill was saved by 20% and the water bill was overspent by 5%. How much water and electricity did the factory save in the second quarter compared with the first quarter?

Reference answer:

1.C 2。 C 3。 C 4 explosive D 5。 C 6。 A

7.( 1)x (2)xy 8.64 9。 - 10 10. 10

1 1.48- 10a- 10b 12。 -7

13.( 1) Original formula = 7a2-6ab. The value is 24.

(2) The original formula =-3x+y2, and the value is 6.

(3) The original formula =-2abc-4ab2-a2b, with a value of 0.

14. Original formula =4

15.2 x2-2x+3-2(x2+6x-6)=- 14x+ 15

16. (m+2m-40)-[80% m+(2m-40) × (1+5%)] = 0.1m+2 (yuan)

15.m =，n =-。 The value is 4.

16.Y 1 = 20× 4+5 (x-4) = 5x+60，y2=(20×4+5x)×92%=4.6x+73.6，y 1=y2，