<span>-(3y-5c)+2(y+c)=-3y+5c+2y+2c=7c-y
<span>4a+3c-3a-4c=a-c
</span><span>3(3k-c)-(3c-k)=9k-3c-3c+k=10k
</span><span>4(y-a)-5(2a-y)=4y-4a-10a+5y=9y-14a
</span><span>2a-y-3a+2y=y-a
</span><span>4(a-x)-2(3a-x)=4a-4x-6a+2x=-2a-2x
</span>-(3a-c)+3(3c-a)=-3a+c+9c-3a=10c-6a
</span>
1
x>0
log(3)x=a
3a²+a-4=0
D=1+48=49
a1=(-1-7)/6=-4/3⇒log(3)x=-4/3⇒x=1/3∛x
a2=(-1+7)/6=1⇒log(3)x=1⇒x=3
2
{log(13)(x²+y²)=2⇒x²+y²=169
{log(5)x-log(5)y=log(5)5-log(5)12⇒log(5)(x/y)=log(5)(5/12)⇒x/y=5/12
12x=5y
y=2,4x
x²+(2,4x)²=169
x²+5,76x²=169
6,76x²=169
x2=169/6,76
x=-13/2,6=-5⇒y=2,4*(-5)=-12
x=13/2,6=5⇒y=2,4*5=12
(-5;-12);(5;12)
Sin(π/2-arccos√3/3)=cos(arccos√3/3)=
=√3/3