1) если х=0, то у=-3
2) <span> x2-2x =-x2+2x,</span>
<span><span> 2x2-4x=0</span></span>
<span><span>х(х-2)=0</span></span>
<span><span>х=0, х=2</span></span>
1)4x/y*y/12x=4/y*y/12=4*1/2=1/3
2)a^3b/15c*(-3c/a^2b^2)=-a^3/15*3*1/a^2b^2=-a/15*3*1/b=-a/5b
3)24p^6/35q^4*49q/16p^4=24p^2/35q^3*49/16=3p^2/5q^3*7/2=21p^2/10q^3
4)18y^3*4x^2/9y^5=2*4x^2/y^2=8x^2/y^2
5)28m^5/23n^4*46n^6=28m^5*2n^2=56m^5n^2
{ 5x - 4y = 13
{ 2x - y = 4
{ x = 13/5 + 4/5y
{ 2x - y = 4
2 ( 13/5 + 4/5y ) - y = 4
y = - 2
2x - ( - 2 ) = 4
x = 1
( x, y ) = ( 1, -2 )
{ 5 * 1 - 4 * ( - 2 ) = 13
{ 2 * 1 - ( - 2 ) = 4
{ 13 = 13
{ 4 = 4
( x, y) = ( 1, -2 )
Ответ: (1; -2)