(40+1)²=40²+2*40*1+1²=1600+80+1=1681
(90+8)²=90²+2*90*8+8²=8100+1440+64=9604
(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
X*x-2x+4x-8-x*x+4x+8x-32=14x-32
14*(-3,5)-32=258
4-x2-x2-1,5x=4
4-4=x2+x2+1,5x
0=2x2+1,5x
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