Решите уравнения:1) 8*(15-d)=642) (t+16):10=83) (9*х-15):42=54) (39-11*х)*207=1242С_Р_О_Ч_Н_О

1) 8 * (15 - d) = 642;

8 * 15 - 8 * d = 642;

120 - 8 * d = 642;

120 - 8d = 642;

-8d = 642 - 120;

-8d = 522;

d = 522 : (-8);

d = -65,25.

2) (t + 16) : 10 = 83;

Домножим обе доли на 10:

(t + 16) : 10 * 10 = 83 * 10;

(t + 16) = 83 * 10;

t + 16 = 83 * 10;

t + 16 = 830;

t = 830 - 16;

t = 814.

3) (9 * х - 15) : 42 = 54;

(9х - 15) : 42 = 54;

Домножим обе доли на 42:

(9х - 15) : 42 * 42 = 54 * 42;

(9х - 15) = 54 * 42;

9х - 15 = 54 * 42;

9х - 15 = 2268;

9х = 2268 + 15;

9х = 2283;

х = 2283 : 9;

х = 253,67.

4) (39 - 11 * х) * 207 = 1242;

(39 - 11х) * 207 = 1242;

39 * 207 - 11х * 207 = 1242;

8073 - 2277х = 1242;

-2277х = 1242 - 8073;

-2277х = -6831;

х = -6831 : (-2277);

х = 3.