Question

966. Решите уравнение:
1) (x - 2,5). 45 = 6,3;
2) 3,5. (x +21)= 14;
3) (1 + x) : 1,9 = 2,5;
4) (7,1 - x): 3,6 = 1​

Answer 1

Пошаговое объяснение:

$(x - 2.5) \times 45 = 6.3 \\ 45x - 112.5 = 6.3 \\ 45x = 6.3 + 112.5 \\ 45x = 118.8 \\ x = 2.64$

$3.5 \times (x + 21) = 14 \\ 3.5x + 73.5 = 14 \\ 3.5x = 14 - 73.5 \\ 3.5x = - 59.5 \\ x = - 17$

$(1 + x) \div 1.9 = 2.5 \\ (1 + x) \div \frac{19}{10} = \frac{5}{2} \\ \frac{10}{19} + \frac{10}{19}x = \frac{5}{2} \\ 20 + 20x = 95 \\ 20x = 95 - 20 \\ 20x = 75 \\ x = 3.75$

$(7.1 - x) \div 3.6 = 1 \\ ( \frac{71}{10} - x) \times \frac{5}{18} = 1 \\ \frac{71}{36} - \frac{5}{18} x = 1 \\ 71 - 10x = 36 \\ - 10x = 36 - 71 \\ - 10x = - 35 \\ x = 3.5$