= [(tg7π/24 - tgπ/24)(tg7π/24 + tgπ/24)] / [(1-tg7π/24*tgπ/24)(1+tg7π/24*tgπ/24)] = [(tg7π/24 - tgπ/24)/(1+tg7π/24*tgπ/24)] * [(tg7π/24 + tgπ/24) / (1-tg7π/24*tgπ/24)] = tg(7π/24 - π/24) * tg(7π/24 + π/24) = tgπ/4 * tgπ/3 = 1 * √3 = √3
1.
y-2=15-3x y=17-3x
<span>-6x+30=2-y
-6x+30=2-(17-3x)
-6x+30=2-17+3x
-6x-3x=2-17-30
-9x=-45
x=5
</span><span>-6*5+30=2-y
</span>-30+30=2-y
-y=-2
y=2
Ответ: (5;2)
2.
-2x+y=-5 y=-5+2x
<span>5x=2-y
</span>
5x=2-(-5+2x)
5x=2+5-2x
5x+2x=2+5
7x=7
x=1
<span>-2*1+y=-5
</span>-2+y=-5
y=-5+2
y=-3
Ответ:(1;-3)
3.
y-3=4x+8 y=4x+11
<span>2x+y=-1
</span>
2x+(4x+11)=-1
2x+4x+11=-1
6x=-12
x=-2
y-3=4*(-2)+8
y-3=-8+8
y=3
Ответ:(-2;3)
4.
3x-4=6-y
<span>y-4=2(x-2) y=2x
</span>
3x-4=6-2x
3x+2x=6+4
5x=10
x=2
y-4=2(2-2)
y-4=0
y=4
Ответ: (2;4)