86400:8=10800 всё для решила
3х^2у×(5х+4у)
.............
AB=√(-5+3)²+(15-2)²=√(4+169)=√173
Sin (π/3 - x/4) = √3 /2(π/3 - x/4) = π/3 +2πnи (π/3 - x/4) = 2π/3 + 2πn
первое решение x/4 = 0 x=0второе x/4 = π/3 - 2π/3 = - π/3 x= - 4π/3
с периодом 2пи
2.8x+61.6-2.2x=74.2
2.8x-2.2x=74.2-61.6
0.6x=12.6
x=21