c^2-2,25=(c-1,5)(c+1,5)
64/81-x^2=(8/9-x)(8/9+x)
0,64-1/9z^2=(0,8-1/3z)(0,8+1/3z)
25x^2-36=(5x-6)(5x+6)
1) 47^2 - 3^2 = ( 47 - 3)*( 47 + 3 ) = 44 * 50 = 2200
2) 27^2 + 2*27*13 + 13^2 = ( 27 + 13)^2 = 40^2 = 1600
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3) 2200 : 1600 = 22 : 16 = 1,375 ( ответ )
Y=2cosx+3
E(cosx)=[-1;1]
E(2cosx)=[-2;2]
E(2cosx+3)=[-2+3;2+3]=[1;5]
Sin30=AC/AB*AC=sin30*AB=1/2*98=49
Подобие треугольников ABC и ACH
AB/AC=AC/AH
98/49=49/AH
AH=49*49/98=24,5