1). 16-c^2=(4-c)*(4+c); 2). p^2+2p+1=(p+1)^2=(p+1)*(p+1); 3). 9m^2-25=(3m-5)*(3m+5); 4). 36m^2+24mn+4n^2=(6m+2n)^2=(6m+2n)*(6m+2n).
<span>27/75 сокращаем на з выходит 9/25</span><span>42/63 сокращаем на 14 выходит 2/3</span>56/60сокращаем на 4 выходит 14/15<span>3*11/11*21 = 33/231=1/7</span><span>15*3/12*25= 45/300=сокращаем на 15 выходит 3/20</span>
Ctg a sin (-a) - cos (-a)=-ctg a sin a - cos a=-<span>cos a/sina *sin a - cos a=
</span>-cos a- cos a=-2<span>cos a</span>
3Y^2 + 8Y + 4 = 0
D = 64 - 4*3*4 = 64 - 48 = 16
V D = 4
X1 = ( - 8 + 4 ) : 6 = ( - 4/6 ) = ( - 2/3 )
X2 = ( - 12 ) : 6 = ( - 2 )
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-6X^2 + 13X - 6 = 0
D = 169 - 4*(-6)*(-6) = 169 - 144 = 25
V D = 5
X1 = ( - 13 + 5 ) : ( - 12 ) = + 8/12 = 4/6 = 2/3
X2 = ( - 18 ) : ( - 12 ) = + 1.5
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X^4 - 13X^2 + 36 = 0
X^2 = A ( A > 0 )
A^2 - 13A + 36 = 0
D = 169 - 4*1*36 = 169 - 144 = 25
V D = 5
A1 = ( - 1 + 5 ) : 2 = 2
A2 = ( - 6 ) : 2 = ( - 3 ) ( < 0 )
X^2 = 2 ---> X = V 2
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