20√3cos(360°+30°) = 20√3 cos30° =(20√3√3)/2=(20*3)/2=10*3=30
так как cos 30°=√3/2, а √3√3=3
(a²-3a)/(a²+3a-18)=a(a-3)/(a-3)(a+6)=a/(a+6)
d=9+72=81
a12=(-3+-9)/2=-6 3
(4x²-8x+3)/(4x²-1)=(2x-1)(2x-3)/(2x-1)(2x+1)=(2x-3)/(2x+1)
в=64-48=16
х12=(8+-4)/8=1/2 3/2
(m²+4m-5)/(m²+7m+10)=(m+5)(m-1)/(m+5)(m+2)=(m-1)/(m+2)
d1=16+20=36
m12=(-4+-6)/2=-5 1
d2=49-40=9
m12=(-7+-3)/2=-5 -2
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44-30+40х=35х+14
40х-35х=14+30-44
5х=0
Х = 0