Вправи: 682

682. Спростіть вираз:

1) 100a + 64a – 121a = 100a + 64a – 121a = 10a + 8a – 11a = 7a;

2) 48 – 27 + 75 = 163 – 93 – 253 = 43 – 33 + 53 = 63;

3) 5b – 12 20b – 500b = 5b – 12 4 5b + 100 5b= 10 5b;

4) 7a + b + 63a = 7a + b + 97a = 7a + b + 37a = 47a + b.