§ 12: 12.11-12.12

12.11 Скоротіть дріб:

1) a12 - 2b12a12 + 2b12 a12 + 2b12 = a12- 2b12;

2) a12 - b12a12 + 2b12 a12b12a12 + b12 = a12 - b12a12b12;

3) (2c13 - 3d13)2(2c13 - 3d13) = 2c13- 3d13;

4) m12 - n12(m12)3- (n12)3 = (m12 - n12)m12 - n12(m + m12n12 + n) = 1m + m12n12 + n;

5) a12(a14+ 7)a12(a12- 49) = (a14+ 7)(a14- 7)(a14+ 7) = 1a14- 7;

6) 615 • 515- 615215 • 515- 215 = 615( 515- 1) 215( 515- 1) = 315 • 215215 = 315.

12.12 Скоротіть дріб:

1) a13(a23+ 2)(a23+ 2) = a13;

2) a12- b(a12+ b)a12(a12- b) = a12+ ba12;

3) x2,5y2,5(x-y)(x0,5- y0,5)2 = x2,5y2,5x0,5- y0,5(x0,5+ y0,5)(x0,5- y0,5)2 = x2,5y2,5(x0,5- y0,5)x0,5- y0,5;

4) a13- 5(a23+ 5a13+ 25)a13- 5(a13+5) = a23+ 5a13+ 25a13+ 5;

6) 814 • 314- 814314 • 214- 214 = 814(314- 1)314(314- 1) = 234214 = 212.