<span> 1) -2а* (-7)* (-5в); 2)-15с* 4 *(-3d); 3)7m* (-8)* 5n; 4)-5а* (-9)* (-4b); 5) 5m* (-6)* (-20n); 6) 125m* 7 * (-8) = -1407.79</span>
(2a-b)×8b+8b×2=16ab+8b=128ab²
Так, если я не ошибаюсь
305:6 — (7⅓ + 2¼) • 4 =
1) 305:6= 50 5/6
2) 7⅓ + 2¼ = 7 4/12 + 2 3/12 = 9 7/12 (9.75)
3) 9 7/12 • 4 = 38⅓
4) 50 5/6 — 38⅓ = 50 5/6 — 38 2/6 = 12 3/6 = 12 ½ (12.5)
3/4x - 2/3x + 1 = 1/2x + 1/6
<span>17(3c+5d)+6c+28d =
</span><span>51c+85d+6c+28d =
</span>57c+113d =
57(с+d) +56d =
57*2 +56d=
114 +56d