help me plz gấp lắm rùi aceeeeeeeeeeeeeeeee ơi Giaỉ các phương trình: a)(2x-1)(xmũ 2-x+1)-2xmũ 3 +3x mũ 2=2 b)(x+1)(x mũ 2)+2x +4)-x mũ 3-3x mũ 2 +16=

Đáp án:

a)(2x-1)(xmũ 2-x+1)-2xmũ 3 +3x mũ 2=2

⇔2x³-2x²+2x-x²+x-1-2x³+3x²=2

⇔(2x³-2x³)+(-2x²-x²+3x²)+2x+x=2+1

⇔3x=3

⇔x=1

b)(x+1)(x mũ 2)+2x +4)-x mũ 3-3x mũ 2 +16=0

⇔x³+2x²+4x+x²+2x+4-x³-3x²+16=0

⇔(x³-x³)+(2x²+x²-3x²)+4x+2x=-16-4

⇔6x=-20

⇔x=-10/3

c) (x+1)(x+2)(x+5)-x mũ 3 -8x mũ 2 =27

⇔(x²+3x+2)(x+5)-x mũ 3 -8x mũ 2 =27

⇔x³+5x²+3x²+15x+2x+10-x³-8x²=27

⇔(x³-x³)+(5x²+3x²-8x²)+15x+2x=27-10

⇔17x=17

⇔x=1

Xin ctlhn nha!!!