Sh. A. Alimov, O. R. Xolmuhamedov, M. A. Mirzaahmedov

a²+ab+x\ 4) х + 6д + 9я².

372. 
     Isbot qiling:
     

1. 
   )(a-bf=(b-af; 4) (a-bf = -(b-af;
   

2. 
   (-a-bf = (b + a)²; 5) (a + bf = a³ +3a²b + 3ab² +b³\
   
3. 
   (-a-b) (a + b) = - (a + b)²; 6) (a-bf = a³ -3a²b + 3ab² -b³.
   

20. 
    § i Kvadratlar ayirmasi formulasi /
    

Ikki son yig‘indisini ulaming ayirmasiga ko‘paytiramiz:
(a + b)(a-b) = a² -ab + ab-b² =a² -b²,
ya’ni
(a + b)(a-b) = a²-b². (1)
a²-b² = (a-b)(a + b). | (2)
Ikki son kvadratlarining ayirmasi shu sonlar ayirmasi bilan ular yig'indisining ko'paytmasiga teng.
(1) va (2) tenglikda a, b istalgan sonlar yoki algebraik ifodalardir, maralan:

1. 
   (nm + 3k)(nm-3k) = n²m² -9k²;
   
2. 
   4c?b² - 25a²b* = (2a²b + 5ab²) (2a²b - 5ab²);
   
3. 
   (a + bf -l6 = (a + b-4)(a + b + 4).
   

Masalan:

1. 
   a²- 9 = (fl-3) (a + 3);
   
2. 
   4- 0,64c² = (2b² f - (0,8c)² = (2b² - 0,8c) (2b² + 0,8c);
   
3. 
   (a-bf -l = (a-b-l) (a-b +1);
   
4. 
   (a + bf -(a-cf = (a + b-a + c)(a + b + a-c) =
   

= (b + c)(2a + b-c).
Mashqlar
(J) formuladan foydalanib, ko‘paytirishni bajaring (386—394):

1. 
   (c + d)(c-d);
   

2. 
   (p + q){p~q)\
   
3. 
   (a + c)(c-d)\
   

1. 
   (x + 5)(x-5);
   

2. 
   (e + 3)(e-3);
   
3. 
   (a-4)(4 + a)\
   

1. 
   (:2b + a)(2b-a);
   

2. 
   (c + 3d)(c-3d);
   

2. 
   (m-n)(m + n);
   
3. 
   (a-b)(-a-b)\
   
4. 
   (2-m)(-2-m).
   

2. 
   (7 + x)(x-7);
   
3. 
   (1 + а)(1-а);
   
4. 
   (6-l)(l + 6).
   

2. 
   (j> + 6x)(6x->>);
   
3. 
   (3m-2n)(2n + 3m).
   

\	( 1 i л	f^1 1 1
; 3)		-y + -*h
\	'2 3 ^4	(2 3 \
; 4)	-m + -n ,^3^4 j	-m — n 3 4 V /

l Y l

1. 
   (c²+d²)(c²-d²);
   

2. 
   (a²+tf)(a²-tf)\
   

391. 1) (За² + 46³) (Зя² - 4b³);

2. 
   (2/я⁴ - 5n²) (5n² + 2/и⁴);
   
3. 
   (*⁴-/)(/₊x⁴);
   
4. 
   (m³-n³)(m³ + я³).
   

2. 
   (0,2r³ +0,5/?⁴)(0,5/?⁴ — 0,2/³);
   
3. 
   (l, 2я² - 0,3b²) (l, 2a² + 0,3b²).
   

o,5 q-^x-p²

392. 1)

3)
4)

A²
Y2

( 3

/V

-a² - -b I 2
2445
-X V
3 5

4 ^H 5 -X +-V 3 5

b + - a 4

I

0,5 q+^p²
' 3 ' 1,5c²--b

/V

393. 
     i) (3х²у-4ху²)(3х²у + 4ху ); 3) (7ab +x²y³)(7ab-x²y³);
     

2. 
   (5ab² + 2a²b)(5ab²-2a²b); 4) (ab³ -4xy)(ab³ +4xy).
   

393. 
     i) (3 + x)(3-x)(9 + x²); 3) (4x²+j/²)(2x + j'Hx-.y);
     

2. 
   (x^: + l)(x + l)(x-l); 4) {3a-2b)(3a + 2b)(9a² +4b²).
   

Qisqa ko‘paytirish formulalaridan foydalanib hisoblang (395—396):

393. 
     i) 48-52; 2) 68-72; 3) 43-37; 4) 47-53.
     
394. 
     i) 47.зз; 2) 44-36; 3) 84 76; 4) 201-199.
     
395. 
     Soddalashtiring:
     

1. 
   (c-3)² -(c + 3)(3-c);
   
2. 
   (я + 2)² -(я + 2)(2-я);
   
3. 
   (2x + 3y)(2x-3>>) + (2x + 3>>)²;
   
4. 
   (3a-4b)(3a + 4b)-(3a-4bf;
   
5. 
   (-b-a)(a + b) + a²+b²;
   
6. 
   (b-a)(-a-b) + 2b².
   

393. 
     ifodaning qiymatini toping:
     

1. 
   4m-(m + 3)² +(m-3)(m + 3), bunda m = -2,4;
   
2. 
   (3x + 4)² -10x-(x-4)(4 + x), bunda x = -0,1;
   
3. 
   2(k-7)(k + 5)-(k-5)²-(k-7)(7 + k), bunda k = ~\
   
4. 
   (fl + 3)² +(fl-3)(3 + fl)-2 (a + 2)(a-4), bunda ⁼
   

393. 
     Tenglamani yeching:
     

1. 
   (2x + 3)² -4(x-l)(x + l) = 49;
   
2. 
   (3x + 4)² -(3x-l)(l +3x) = 49;
   

3. 
   (3jc + 2)(3x-2)-(3x-4)²=28;
   
4. 
   (Зх + 1)² -(3x-2)(2 + 3a) = 17.
   

400. 
     Kvadratning ikki qarama-qarshi tomonining har bin 8 sm ga uzaytirildi, qolgan ikki tomoni esa shuncha qisqanirildi. Shakl­ning yuzi qanday o'zgardi?
     
401. 
     Hisoblang: ^ 0,128-5’.Q,628o 125 0,25
     

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