1) (40 : х) × 14 = 70;
(40 : х) = 70 : 14;
40 : х = 5;
х = 40 : 5;
х = 8.
2) 280 : (x - 10) = 7;
(х - 10) = 280 : 7;
х - 10 = 40;
х = 40 + 10;
х = 50.
3) b × 100 + 500 = 1000;
b × 100 = 1000 - 500;
b × 100 = 500;
b = 500 : 100;
b = 5.
4) x + 24 × 19 = 480;
х + 456 = 480;
х = 480 - 456;
х = 24.
5) (32 - k) × 3 = 9;
32 - k = 9 : 3;
32 - k = 3;
k = 32 - 3;
k = 29.
89 + a ÷ 4 = 63;
а : 4 = 63 - 89;
а : 4 = -26;
а = -26 × 4;
а = -104.
1) (40 : х) × 14 = 70;
(40 : х) = 70 : 14;
40 : х = 5;
х = 40 : 5;
х = 8.
2) 280 : (x - 10) = 7;
(х - 10) = 280 : 7;
х - 10 = 40;
х = 40 + 10;
х = 50.
3) b × 100 + 500 = 1000;
b × 100 = 1000 - 500;
b × 100 = 500;
b = 500 : 100;
b = 5.
4) x + 24 × 19 = 480;
х + 456 = 480;
х = 480 - 456;
х = 24.
5) (32 - k) × 3 = 9;
32 - k = 9 : 3;
32 - k = 3;
k = 32 - 3;
k = 29.
89 + a ÷ 4 = 63;
а : 4 = 63 - 89;
а : 4 = -26;
а = -26 × 4;
а = -104.