489. Решите уравнение: 1) 21(18 + x) = 714;

Решение уравнений: **489** 1) $21(18 + x) = 714$ -> $18 + x = 34$ -> $x = 16$ 2) $16(4x - 34) = 608$ -> $4x - 34 = 38$ -> $4x = 72$ -> $x = 18$ 3) $12(152 + 19x) = 2052$ -> $152 + 19x = 171$ -> $19x = 19$ -> $x = 1$ 4) $(152x + 32) \cdot 6 = 192$ -> $152x + 32 = 32$ -> $152x = 0$ -> $x = 0$ **490** 1) $8(x - 14) = 56$ -> $x - 14 = 7$ -> $x = 21$ 2) $(46 - x) \cdot 19 = 418$ -> $46 - x = 22$ -> $x = 24$ 3) $9(143 - 13x) = 234$ -> $143 - 13x = 26$ -> $13x = 117$ -> $x = 9$ 4) $17(5x - 16) = 238$ -> $5x - 16 = 14$ -> $5x = 30$ -> $x = 6$ **491** 1) $14x + 4x - 48 = 240$ -> $18x = 288$ -> $x = 16$ 2) $25b - 7b - 9 = 279$ -> $18b = 288$ -> $b = 16$ 3) $16a - 7a + 96 = 222$ -> $9a = 126$ -> $a = 14$ 4) $20y + 5y + y + 19 = 227$ -> $26y = 208$ -> $y = 8$ **492** 1) $9b + 6b - 15 = 615$ -> $15b = 630$ -> $b = 42$ 2) $2a + 123a + 97 = 472$ -> $125a = 375$ -> $a = 3$ 3) $17x - x + 5x - 19 = 170$ -> $21x = 189$ -> $x = 9$ 4) $73y - y - 22y + 40 = 190$ -> $50y = 150$ -> $y = 3$ **493** 1) $(x + 14) : 9 = 13$ -> $x + 14 = 117$ -> $x = 103$ 2) $966 : (x + 17) = 23$ -> $x + 17 = 42$ -> $x = 25$ 3) $x : 8 - 6 = 49$ -> $x : 8 = 55$ -> $x = 440$ 4) $52 + 72 : x = 56$ -> $72 : x = 4$ -> $x = 18$ 5) $56 : (x - 6) = 8$ -> $x - 6 = 7$ -> $x = 13$ 6) $56 : x - 6 = 8$ -> $56 : x = 14$ -> $x = 4$