Х²-5х-6=0
По теореме Виета
{х1+х2=5
{х1*х2=-6
{х1=6
{х2=-1
(sina-cosa)²=sin²a-2sinacosa+cos²a=1-2sinacosa
2sinacosa=1-(sina-cosa)²
<span>sinacosa=[1-(sina-cosa)²]/2
</span>sinacosa=(1-0,36):2=0,64:2=0,32
−6t2(2t7−3k)+5(4t9−2k)= -12t(14t-3k) +(900t-10k) =-168t+36tk+900t-10k=-168t+26tk+10tk+900t-10k=-142t+k+t+900t=758t+t+k=759t+k