А10. tg (2π - π/4) = tg π/4 = 1
В1 Cos² a = 1 - Sin² a = 1 - 91/100 = 9/100
Cos a = 3/10
В2 4√2·Сosπ/4·Сos7π/3 = 4√2·√2/2·1/2= 2
1)a^2-2a+1=(a-1)^2
2)4x^2+4xy+y^2=(2x+y)^2
3)4b^2+28ab+49a^2=(2b+7a)^2
4)0,25n^2+10mn+100m^2=(0,5n+10m)^2
5)b^2+8ab+16a^2=(b+4a)^2
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0 - y = -1
y = 0 - ( -1 )
y = 1
Ответ: 1
Проверка:
0 - 1 = -( 1 - 0 ) = -1
2x-7/6-2/3=5(3-x)/4=>
=>8x-22/3=15-5x=>
=>13x=15+22/3=>
=>13x=67/3=>
=>x=67/39=>
=>x=1 28/39;
Ответ:1 28/39.