The answer to the first semester math in winter vacation homework junior high school is 202 1.
1、 =-0.5 =2
2. Omission
3. Omission
4、- 1.50062× 10^4
5、-0.00203
6 、- 1/( 1+2a) -3/(2ab？ (x-y)
7 、& lt-2.5
8, expand 5 times
Multiple choice ABC
12 、( 1)= b/(a+b)(2)= 3/(x- 1)(3)=(x-y)？ /xy×xy/(x+y)？ = (x？ -2xy+y？ )/(x？ +2xy+y？ )(4)=(32x^7)/(9 y^3)
13、x- 12=2x+ 1 x= 1
14 and (1) x are brought into the original formula = (-2/5–2k)/-6/5k = 8/5k =-5.
(2) The original formula =x? /(x？ +x) When x=- 1/2, the original formula =- 1.
15, the reciprocal of the original formula =3(x? + 1/x？ - 1)=-9/4
16, the original formula = (a+ab+ABC) ÷ (a+ab+ABC) =1.
17, let Xiao Li x, Xiao Wang x+2. 60/(x+2)=48/x x=8 x+2= 10
1, (1) right 4 down 5 down 5 right 4 point a' point B' ∠C' line segment B'C'
(2) the same distance
(3) Equality, equality, equality
(4) Shape
(5) Distance
(6) Omission
2. Draw this picture yourself.
(1) fixed point This fixed point
(2) The centers of rotation are equal, equal and equal.
(3) Size and shape
(4) Omission
Step 3 draw by yourself
(1) 180 Another figure Two figures, this point, the two figures form the intersection of central symmetry and symmetry.
(2) The rotation angle of the initial rotation center is 0.
(3) 180 Symmetry Center of Initial Graph
(4) Omission
Step 4 draw by yourself
(1) is an axisymmetric straight line.
(2) Equality, equality, sameness and invariability
(3) perpendicular to the midpoint of two pairs of corresponding points
(4) Axisymmetric graphic straight lines that coincide with each other.
(5) The median perpendicular to the midpoint of countless sides of a straight line passing through the center of the circle.
(6) Omission
5, C 90 point A point E line segment CA line segment CE ∠A AC midpoint Q isosceles right angle.
1, draw all by yourself.
2. Sketch (2) Rotate clockwise 1 19 or counterclockwise 24 1.
3.Sketch (1) translates A'B' and A' B', A'C' and A' c', B'C' and B' c'.
(2) Rotate 90 degrees counterclockwise.
(3) Rotate180 counterclockwise (clockwise) around the O point (the O point itself is marked on the map).
1, translation, rotation and folding
2. Location, shape and size
3、 90
4, the center of the circle
5、 8
6.yes, yes
7, high temperature oxidation
8. Translate, rotate and fold dimensions and shapes.
9、C
10、D
1 1、C
12, sketch
13, sketch
14, sketch
15, sketch
16, sketch
17, point c, point b, midpoint of BC line.
18, let EC be x cm. 8∶5=x∶4 x=6.04
1、2a^7 (y？ x？ )/x？ y？
2、3/2m？ x -2/(x+3)
3、xy(y-x)(x+ 1)(x- 1)(x+3)(x-3)
4 、(-3y？ )/x？ z
5、6
6, equilateral triangle
7、 169/4 π
Multiple choice question CB
10 、( 1)=2a/(a-b) (2)= 1/a？ b？
1 1、x=- 1 x=5/4
12, sketch S Yin = 8×10.04/2-5× 6.04/2 = 25.06cm?
13, sketch
14, original formula =2/(x+ 1)? When ..., the original formula =8.
15、A-B=2 3A-2B= 1 A=-3 B=-5
16, x grams x/(235+x)=6% x= 15.
17, sketch
18, the book has
Preview real numbers in the new semester
1, a< four
2、 9 9
3、 0
4、 3-√7
5、 -0.5
6. A.
7、 ≥ 1
8. Omission
9,2 real number even number 1 positive number 1 negative number
10,3162277660 plus BCAC, multiple choice questions with circulation points.
15、 1 1
16 、( 1)x = 30(2)x- 1 = 0.25 x = 5/4
17、a= 1.5 m=a？ =9/4
18、4-2x≥0