1)12а-2(а^2+6a+9)=12a-2a^2+12a-18=-2a^2-18=<span>√-9
2)32a+2(a+8)=32a+2(a^2+16+64)=32a+2a^2+32a+128=2a^2+64a+128=a^2+32+64
3)x^2-8xy+16y^</span>2+10x^2+8xy=11X^2+16y^2= 16y^2=-55 Y=<span>√-55/16
4)8y^2-12xy-9x^2+12xy-4y^2=4y^2-9x^2=12-63=-51
5)6ab+3a^2-6ab+3b^2=6-9=-3
</span>
(3cos28°cos34°-3cos62°cos56°)/(sin74°cos46°-cos44°sin16°)
=
=3(cos28cos34-sin28sin34)/(cos16sin44-cos44sin16)=
=3cos(28+34)/sin(44-16)=3cos62/sin28=3sin28/sin28=3
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используем формулы
sin(π/2-a)=cosa
cos(π/2-a)=sina
cosacosb-sinasinb=cos(a=b)
sinacosb-cosasinb=sin(a-b)
-0,4а(10а-6а²+15-9а)=-0,4а(-6а²+а+15)=0,4а(6а²-а-15)
3482=3,482*10³
0,963=9,63*10^-1
570000=5,7*10^5
42,95=4,295*10
561,453=5,61453*10²