<span>по т. Пифагора
СВ=√АВ2 АС2 =3</span>sinA=CB/AB=3/5=0,6cosA=AC/AB=0,8tgA=CB/AC=3/4sinB=AC/AB=4/5=0,8cosB=CB/AB=3/5=0,6<span>tgB=AC/CB=4/3</span>
2.5y-4=0
y=4:2.5=1.6
6y+1.8=0
y=-1.8:6=-0.3
<span>Распределительное свойство умножения</span>: (a+b)*c=ac+ab.
<span>а) 3 1/9:2 1/3=28/9*3/7=4/3=1 1/3 б)16/21:20/49=16/21*49/20=28/15=1 13/15 в) 3 2/9:2</span>=29/9*1/2=29/18=1 11/18 г)1 2/3:2 1/2=5/3*2/5=2/3
д)17/30:34/75=17/30*75/34=5/4=1 1/4 е)3:1 2/3=3/1*3/5=9/5=1 4/5
ж)15/28:40/49=15/28*49/40=21/32 з)???? и)????