Если Ctg2α = 1/3 , то
a)
t(t+5)=0
<span>t=0 ∨ t=-5</span>
b)(2x+1)(3x-9)=0
2x+1=0
2x=-1
<span>x=-1/2</span>
3x-9=0
3x=9
<span>x=3</span>
x²+3≠0
x²≠-3
x²-64=0
x²=64
<span>x=-8 ∨ x=8</span>
b)
x²-9≠0
x²≠9
x≠-3 ∧ x≠3
x²-3x=0
x(x-3)=0
<span>x=0</span>
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