Вычислите: (тема "Формулы Сокращенного Умножения")

1) (30+1) (30-1) ;

2) 61•59; 3) 199•201;

4) 72•68;

5) 55²-45²;

6) 41²-31²;

7) 76²-24²;

8) 37²-23².

1) 30^2-1^2=900-1=899;

2) 61*59 = (60+1) (60-1) = 3600-1=3599;

3) (200-1) (200+1) = 40000-1=39999; 4) (70+2) (70-2) = 4900-4=4896; 5) (55-45) (55+45) = 10*100=10000; 6) (41-31) (41+31) = 10*72=720; 7) (76-24) (76+24) = 52*100=5200; 8) (37-23) (37+23) = 14*60=840

1) (30+1) (30-1) = 30 ² - 1² = 900 - 1 = 899

2) 61 * 59 = (60 + 1) (60 - 1) = 3600-1 = 3599

3) 199 * 201 = (200 + 1) (200 - 1) = 40000 - 1 = 39999

4) 72 * 68 = (70 + 2) (70 - 2) = 4900 - 4 = 4896

5) 55² - 45² = (55 - 45) (55 + 45) = 3025 - 2025 = 1000

6) 41² - 31² = (41 - 31) (41 + 31) = 1681 - 961 = 720

7) 76² - 24² = (76 - 24) (76 + 24) = 5776 - 576 = 5200

8) 37² - 23² = (37 - 23) (37 + 23) = 1369 - 529 = 840