Question

数学问题(急急急急急急........)

Answer 1

3r+4s-2r+7s =3r-2r+4s+7s =r+11s 4x2-2x+7-2x+3x2+5x-2 =4x2+3x2-2x-2x+5x+7-2 =7x2+x+5 a+2b+3c+4a-6b-2c =a+4a+2b-6b+3c-2c =5a-4b+c 2xy+3x-2y+4x-6y+ 5xy =4x+3x+2xy+ 5xy-2y-6y =7x+7xy-8y 4x+2xy/3y =4x+2x/3 ={(4x)3+2x}/3 =(12x+2x)/3 =14x/3 (x+1)/y+(y+1)/x ={(x+1)x+(y+1)y}/xy =(x2+x+y2+y)/xy [[optional]]
参考: me*
9a)3r+4s-2r+7s =3r-2r+4s+7s =r+10s b)4x的2次方-2x+7-2x+3x的2次方+5x-2 =4x的2次方+3x的2次方-2x+5x+3x-2 =7x的2次方+7x-2 c)a+2b+3c+4a-6b-2c =a+4a+2b-6b+3c-2c =5a-4b+c d)2xy+3x-2y+4x-6y+5xy =2xy+5xy+3x+4x-2y-6y =7xy+7x-8y a.) 4x+3y分之2xy = 4x+3分之2x =3分之14x b.)y分之x+1+x分之y+1 =xy分之x2次方+x+y2次方+y
参考: me