Kneel down and ask for answers to the first math review case 20 21 9 10 18 19 25

,y=5

19.Because the angle between every two squares is 30 degrees, so from 6 o'clock when you go home less than 7 o'clock you can know that the hour hand moves away from the car can not be more than 30 degrees, because the angle between the hour hand and minute hand is 110 degrees, so when he goes out more than 6 10 (4 30 ° = 120 °), when he arrives at home the closed crack is not 7 o'clock, the angle is still 11 pins and ten degrees, he arrived home at more than 6:50, because the angle between the hour hand and the minute hand has not changed, he can be pushed out and walked for 40 minutes.

20 Questions: Draw Your Own Pictures-

This triangle ABC is an isosceles right triangle with C to A distance and C in the direction of due north of A.

Let the angle be x, then its co-angle is (90°-x), and the complementary angle is (180°-x), which is solved by the equation 90°-x=2 9(180°-x)+1 x=63°

2. Let the angle with the smallest degree be x, and the other angle is (180°-x) and the columnable equation (180°-x)-x=20°

The solution is x=80°

I've been playing for so long, like it, 2333

18、a

19、=2√3-2√7-3√3-3√7=-√3-5√720、=2x2x3=12

If you have solved your doubts, please click Satisfied in the upper right corner, thank you.

19. 1=47°, the top is equal to ABC=47°, 2=133°, 2 is complementary to BCD=180° -133°=47°

So: abc= bcd=47° isotope angle equal so :ab cd

bcd=47°,∠d=47°

bcd = the wrong angles within d are equal, so bc de

20、∵ef⊥eg,gm⊥ge,ef∥gm,ef⊥eg,gm⊥ge,∠1=35°,∠2=35°,∴aeg=∠cgn,ab∥cd．

So the answer is: EF GM, AB CD

21. Solution: CM is parallel to DN.

Proof: 1=70°

dcf = 180°- 1 = 180° - 70° = 110 ° and cm bisect dcf

My reply is as follows, and I invite you to consider it.

20 questions: (1) = a (x-y)-b (x-y) = (x-y) (a Beizhou Zheng -b ) = x-y) (a + b) (a-b).

2) Traces contain = [(x -5)+4] =x -1) =x+1) (x-1) imitation = (x+1) (x-1).

21 Questions: =(3x+2)(3x-2)-5x(3x-2)+(3x-2) =3x-2)(3x+2-5x+3x-2)=x(3x-2)=5 12

If you fill in the 19 questions correctly, you can leave the first blank blank blank.

Question 20 (1) 7 pairs of isotopic angles, 6 pairs of internal wrong angles, and 17 pairs of isolateral internal angles.

2) That's right.