Question

a) (x+y)+(y-x) b) (x+y)-(y-x) c) (x-y)+(y-x) e) (x²+xy-1)+(3x²+xy+1) g) (x²+xy-1)-(3x²+xy+1)

Answer 1

Chúc bạn học tốt 🙆‍♀️❤

Answer 2

Tiếp thu và sửa đổi. Cảm ơn ạ 🙆‍♀️

\(a) (x+y)+(y-x)\)

\(= x+y+y-x\)

\(=(x-x)+(y+y)\)

\(= 2y\)

\(b) (x+y)-(y-x)\)

\(= x+y-y+x\)

\(= (x+x)+(y-y)\)

\(= 2x\)

\(c) (x-y)+(y-x)\)

\(= x-y+y-x\)

\(= (x-x)+(y-y) \)

\(=0\)

\(e) (x^2+xy-1)+(3x^2+xy+1)\)

\(= x^2+xy-1+3x^2+xy+1\)

\(= (x^2+3x^2)+(xy+xy)+(1-1)\)

\(= 4x^2 + 2xy\)

\(g) (x^2+xy-1)-(3x^2+xy+1)\)

\(= x^2+xy-1-3x^2-xy-1\)

\(= (x^2-3x^2)+(xy-xy)-(1+1)\)

\(= -2x^2 - 2\)