A²+b²=101, a+b=13
(a+b)²-2ab=101, 13²-2ab=101,2ab=169-101,2ab=68, ab=34
ab=34
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Sinx-cos3xsinx=0
sinx(1-cos3x)=0
sinx=0⇒x=πn
cos3x=1⇒3x=2πn⇒x=2πn/3
9 - 6x + x^2 - ( x^2 - 9) + 5x + 22 = 9 - 6x + x^2 - x^2 + 9 + 5x + 22 =
= - x + 18 + 22 = 40 - x
11х-6х^2-20+4x^2-20x+25=0
-2x^2-9x+5=0
Д=81+40=121
х1=-5
х2=0,5