график у=2,5х, у=-4,5х
<span>1) (x-3y)(3y+x)=x^2-9y^2</span>
2) (x-2)^2+8x=(x-1)(1+x)
<span> (x-2)^2+8x=x^2-1</span>
x^2-4x+4+8x-x^2+1=0
4x+5=0
4x=-5
x=-1.25