\(C=x^2-5y^2+x-3y\)
\(C=x^2-y^2-4y^2+x-3y\)
\(C=\left(x-y\right)\left(x+y\right)-4y^2+x-3y\)
\(C=x-y-4y^2+x-3y\)
\(C=-4y^2+2x-4y\)
\(C=-4y^2-4y-1+2x+1\)
\(C=-\left(2y-1\right)^2+2x+1\)
\(C=-\left(2y-x-y\right)^2+2x+x+y\)
\(C=-\left(y-x\right)^2+3x+y\)
bn làm tiếp nha