The seventh grade mathematics volume II algebraic expression multiplication unit examination questions.
First, multiple-choice questions (30 points)
1, the following operation is correct ()
A.a2？ a3 = a6b .(-a+b)(a+b)= B2-a2； c .(a3)4 = a7； a3+a5=a8
2. If the result of calculating (x2-3x+n)(x2+mx+8) does not contain x2 and x3, then the values of m and n are ().
A.m=3，n = 1； B. m=0，n = 0； C. m=-3，n =-9； D. m=-3，n = 8；
3. We agreed that a b= 10a? 10b, for example: 2 3 =102? 103= 105, so 4 8 is ()
A.32; b . 1032； c . 10 12； d . 12 10；
4. If (xnym)3=x9y 15, the values of m and n are ().
A.m=9，n =-5； B. m=3，n = 5； C. m=5，n = 3； D. m=9，n = 3；
5. The result of calculating -(-3a2b3) 4 is ().
A.8 1a8b 12； b . 12 a6b 7； c .- 12 a6b 7； d .-8 1a8b 12；
6. Calculate that 1982 is equal to ()
A.39998; B. 39996C. 39204D. 39206
7. If, then the value of a+b is ().
A.； b； c . 1； d . 2；
8, the following operation error is ()
A.； b； c； d；
9. What if? 3ab=3a2b, then the algebraic expression to be filled in is ()
A.ab； B. 3abc . a； D. 3a
10, put four rectangular cards with the same shape and size.
(as shown in figure ①) placed at the bottom of the rectangle without overlapping.
(m cm long and n cm wide) (as shown in Figure 2),
The part of the bottom surface of the box that is not covered by the card is shaded,
Then the sum of the perimeters of the two shaded parts in Figure ② is ()
A.4m cmB. 4n cmc . 2(m+n)cm； D. 4 (male-female) cm;
Two. Fill in the blanks: (24 points)
1 1, calculation: =.
12, when x=3 and y= 1, the value of algebraic expression (x+y)(x-y)+y2 is.
13, calculation: =.
14. If (m-n) 2=8 and (m+n) 2=2, then m+n=.
15. If the length of a rectangle with a length of x and a width of y increases by 3 and the width decreases by 3, the area will increase.
16, calculation: =.
17, define a new operation, specify: a b=, then 12 (- 1)=.
18, the four numbers A, B, C and D are arranged in two rows and two columns, and a vertical bar is added to each side, which is recorded as,
Definition =ad-bc, the notation above is called second-order determinant, if =6, then x=.
Iii. Answering questions (46 points)
19, (16 points) Calculate the following questions:
( 1) (2) (x-y-5)(x+y-5)
(3)(4)(x+2)(x+3)-(x+ 1)(x-2)
20.( 10) Simplify before evaluating:
(1) x (x+2)-(x+1) (x-1), where x=
(2) (x+y) 2 (x-y) 2-(x-y) (x+y) (x2+y2), where x= and y=-2.
2 1, (5 points) Solve the equation: 4 (x-3) 2-(2x+1) 2 = (3x+1) (1-3x)+9x2.
22.(7 points) Given a-b=2 and a-c=, find the value of the algebraic formula (b-c) 2-3(b-c)+.
23.(8 points) Read the materials and answer questions: Calculate:
( 1)(x- 1)(x+ 1)= x2- 1
(x- 1)(x2+x+ 1)= x3- 1
(x- 1)(x3+x2+x+ 1)= x4- 1
?
Guess: (x- 1)( xn+xn- 1+? +x2+x+ 1)=x4- 1=。
(2) According to the above results, write the results of the following formula:
(x- 1)( x49+x48+？ +x2+x+ 1)=x4- 1=。
(3) From the above situation, can you find out the result of the following formula? Write the results directly if you can ask, and explain the reasons if you can't ask.
(x20- 1)？ (x- 1)= .
The multiplication reference answer of algebraic expression of unit test questions in the second volume of seventh grade mathematics.
1. 1，b； 2、A； 3、C； 4、C； 5、D；
6、C； 7、A； 8、A； 9、B； 10、A；
Second, 1 1, a2bc6 12, 9; 13、A8-2a4 B4+b8； 14、5; 15、3y-3x-9；
16 、- x8 17、8;
Iii. 19, (1) Original formula = 6x5y3-6x4y2; (2) The original formula = x2-10x+25-y2;
(3) original formula = 4a6(4) original formula = 6x+8;
20. (1) The original formula =2x+ 1. When x=, the original formula = 0;
(2) The original formula =2y4-2x2y2, and when x= and y=-2, the original formula = 30;
22、∫a-b = 2，a-c=，？ b-c=
Original formula = =9
23 、( 1)x，4- 1，x，n+ 1- 1；
(2)x，50- 1，