1)8/7-23/49=56/49-23/49=33/49
2)(33/49)/(22/147)=33/49*147/22=3/1*3/2=9/2
3)6/10*4/15=12/225
4)12/225*5/2=6/45
5)9/2-6/45=(405-12)/90=393/90=131/30
6)3,75 : 1 1/2=15/4*2/3=5/2
7)131/30+5/2=(131+225)/30=356/30=178/15
8)178/15:2.2=178/15*5/11=178/3*1/11=178/33
1) f(x)=5cos²x-3
f `(x)=-5sin2x
f `(п/6) = -5sin2*п/6= (-5√3)/2
2) f(x)=-sinx+x
f `(x)=-cosx+1
f `(0)=-cos(0)+1=0
7z*(x-y)-5*(y-x)=7z*(x-y)-5*(-(x-y))=7z*(x-y)+5(x-y)=(x-y)*(7z+5)
А)
(9/5)х>=0 ¦*(5/9)
x>=0
б)
(5+6x)/2>3
5+6x>6
6x>1
x>(1/6)