4x-5 ≥ 2x-4
4x - 2x ≥ 5 - 4
2x ≥ 1
x ≥ 1/2
x є [ 1/2 ; +∞)
5.2*(0.1)/0.13*(0.4)= 100
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1-2(2sin(П/2+а)•
•cos(П/2+а))^2=1-2•
(sin(П+2а))^2=
=(cos(П+2а))^2 +(sin(П+2а)^2)- -2(sin(П+2а)^2=cos(2П+4а)=cos(4a)
<span>(2a+1)^2-(a-9)^2=(2a+1-a+9)(2a+1+a-9)= (a+10)(3a-8)</span>