\(\text{a) }x^4+x^2y^2+y^4=x^4+2x^2y^2-x^2y^2+y^4=\left(x^4+2x^2y^2+y^4\right)-\left(x^2y^2\right)=\left(x^2+y^2\right)^2-\left(xy\right)^2\)
\(=\left(x^2+y^2+xy\right)\left(x^2+y^2-xy\right)\)
\(\text{b) }x^3+3x-4=x^3+3x-1-3=\left(x^3-1\right)+\left(3x-3\right)=\left(x-1\right)\left(x^2+x+1\right)+3\left(x-1\right)\)
\(=\left(x-1\right)\left(x^2+x+1+3\right)=\left(x-1\right)\left(x^2+x+4\right)\)
\(\text{c) }x^2+9x+8=x^2+8x+x+8=\left(x^2+8x\right)+\left(x+8\right)=x\left(x+8\right)+\left(x+8\right)\)
\(=\left(x+8\right)\left(x+1\right)\)
\(\text{d) }x^2+x-42=x^2+7x-6x-42=\left(x^2+7x\right)-\left(6x+42\right)=x\left(x+7\right)-6\left(x+7\right)\)
\(=\left(x+7\right)\left(x-6\right)\)
\(\text{e) }y^2-13y+12=y^2-y-12y+12=\left(y^2-y\right)-\left(12y-12\right)=y\left(y-1\right)-12\left(y-1\right)\)
\(=\left(y-1\right)\left(y-12\right)\)
Mấy câu sau mk sẽ giải tiếp, bạn ráng chờ nha
\(\text{f) }x^2-x-30=x^2+5x-6x-30=\left(x^2+5x\right)-\left(6x+30\right)=x\left(x+5\right)-6\left(x+5\right)\)
\(=\left(x+5\right)\left(x-6\right)\)
\(\text{g) }2x^2+xy-y^2=x^2+x^2+xy-y^2=\left(x^2-y^2\right)+\left(x^2+xy\right)=\left(x-y\right)\left(x+y\right)+x\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y+x\right)=\left(x+y\right)\left(2x-y\right)\)
\(\text{h) }y^2-y-12=y^2+3y-4y-12=\left(y^2+3y\right)-\left(4y+12\right)=y\left(y+3\right)-4\left(y+3\right)\)
\(=\left(y+3\right)\left(y-4\right)\)
\(\text{i) }x^2+x-2=x^2+2x-x-2=\left(x^2+2x\right)-\left(x+2\right)=x\left(x+2\right)-\left(x+2\right)\)
\(=\left(x+2\right)\left(x-1\right)\)
\(\text{j) }x^3+3x^2-2=x^3+3x^2+1-3=\left(x^3+1\right)+\left(3x^2-3\right)\)
\(=\left(x+1\right)\left(x^2-x+1\right)+3\left(x^2-1\right)=\left(x+1\right)\left(x^2-x+1\right)+3\left(x+1\right)\left(x-1\right)\)
\(=\left(x+1\right)\left(x^2-x+1\right)+\left(x+1\right)\left(3x-3\right)\)
\(=\left(x+1\right)\left(x^2-x+1+3x-3\right)\)
\(=\left(x+1\right)\left(x^2+2x-2\right)\)
\(\text{k) }x^3-6x^2-16\left(\text{bài này mk k làm được}\right)\)
\(\text{l) }x^3+3x+4=x^3+4x-x+4=\left(x^3-x\right)+\left(4x+4\right)=x\left(x^2-1\right)+4\left(x+1\right)\)
\(=x\left(x+1\right)\left(x-1\right)+4\left(x+1\right)=\left(x+1\right)\left(x^2-x\right)+4\left(x+1\right)=\left(x+1\right)\left(x^2-x+4\right)\)
Câu m) mk k biết
Ban đăng thêm câu hỏi về các câu mk k làm được để cho người khác giải nha