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=0
c) (x+1)(x+2)(x+5)-x mũ 3 -8x mũ 2 =27
gợi ý kết quả
a)x=1
b)x=âm 10 phần 3
c)x=1
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=0
c) (x+1)(x+2)(x+5)-x mũ 3 -8x mũ 2 =27
gợi ý kết quả
a)x=1
b)x=âm 10 phần 3
c)x=1
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!!!
`a)(2x-1)(x²-x+1)-2x³+3x²=2`
`⇔2x³-2x²+2x-x²+x-1-2x³+3x²=2`
`⇔3x-1=2`
`⇔3x=2+1`
`⇔3x=3`
`⇔x=1`
Vậy `S={1}`
`b)(x+1)(x²+2x+4)-x³-3x²+16=0`
`⇔x³+2x²+4x+x²+2x+4-x³-3x²+16=0`
`⇔6x+20=0`
`⇔6x=-20`
`⇔x=-10/3`
Vậy `S={-10/3}`
`c)(x+1)(x+2)(x+5)-x³-8x²=27`
`⇔(x²+2x+x+2)(x+5)-x³-8x²=27`
`⇔(x²+3x+2)(x+5)-x³-8x²=27`
`⇔x³+5x²+3x²+15x+2x+10-x³-8x²=27`
`⇔17x+10=27`
`⇔17x=27-10`
`⇔17x=17`
`⇔x=1`
Vậy `S={1}`