Y=2-x-x^ y=0
2-x-x^=0
(2-x-x^)÷(-1)=0
x^+x-2=0
D=1^-4×(-2)=1+8=9=3^
x1\2=(-1+\-3)2=1\-2
x1=-2; x2=1
А)-5a³(2a²-a-3)=-5a³*2a²-a*(-5a³)-3*(-5a³) = -10а^5+5а^4+15а³<span>
б)(3c-a)*(2c-5a)=</span>2c*3c-5a*3c-a* 2c-5a*(-a) = 6с²-15ас-2ас+5а² = 6с²-17ас+5а²<span>
в)(3x+2y)²=9х</span>²+12ху+4у²