(m-32,6)*2,4=1,8
2,4m-78.24=1.8
2.4m=1.8+78.24
2.4m=80.04
m=80.04:2.4
m=33.35
3,4х+1,8х=43,16
5.2х=43,16
х=43,16:5,2
х=8,3
(8x-9y-21)*2+(3x-2y-12)*(-9)=0;
-11x=-66;
x=6
y=3
<span>(5 / 14 + 10 / 21) × 18 / 10 + 7 / 6 / (13 / 22 – 25 / 33) = (15/42 + 20/42) * 18/10 + 7/6 : (39/66 - 50/66) = 35/42 * 18/10 + 7/6 : (-11/66) = 7/7 * 3/2 + 7/6 * (-66/11) = 21/14 + 7/1 * (-11/11) = 3/2 + (-7) = 3/2 + (- 14/2) = - 11/2 = - 5,5</span>
( 2,8 * 3600 * 1,2 + 2,2 *3600* 0,9) / (2,2*3600+2,8*3600) = 1,068 м/с