Question

Giải phương trình

 a /(x - 1)( x² + 3x - 2 ) - (x³ - 1) =  0

b/ ( x³ + x² ) + ( x² + x ) = 0

c/ x³ - 7x + 6 = 0

d/ x⁴ + 6 = 5x²

 

Answer 1

d, x⁴+6=5x²

x⁴-5x²+6=0

x⁴-2x²-3x²+6=0

x²(x²-2)-3(x²-2)=0

(x²-1)(x²-3)=0

\(\Rightarrow\orbr{\begin{cases}x^2-1=0\\x^2-3=0\end{cases}\Rightarrow\orbr{\begin{cases}x^2=1\\x^2=3\end{cases}\Rightarrow}\orbr{\begin{cases}x=+-1\\x=+-3\end{cases}}}\)

Vay pt tren co tap nghiem S={+1;+3}

Answer 2

a, (x-1)(x²+3x-2)-(x³-1)=0

(x-1)(x²+3x-2)-(x-1)(x²+x+1)=0

(x-1)(x²+3x-2-x²-x-1)=0

(x-1)(2x-3)=0

\(\Rightarrow\orbr{\begin{cases}x-1=0\\2x-3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=\frac{3}{2}\end{cases}}}\)

Vay phuong trinh tren co tap nghiem la : \(S=\left(0;\frac{3}{2}\right)\)

Answer 3

b, (x³+x²)+(x²+x)=0

x²(x+1)+x(x+1)=0

(x+1)(x²+x)=0

x(x+1)(x+1)=0

x(x+1)²=0

=>x=0

Ma : (x+1)² >0 => vo nghiem.

Vay phuong trinh tren co x=0

Answer 4

c, x³-7x+6=0

x³-x-6x+6=0

x(x²-1)-6(x-1)=0

x(x-1)(x+1)-6(x-1)=0

(x-1)[x(x+1)-6]=0

(x-1)(x²+x-6)=0

Ma : x²+x-6>0 => vo nghiem

=>x-1=0=>x=1

Vay phuong trinh tren co nghiem x=1

Answer 5

x + ( X+1 ) + ( X+2 ) + ( X+3) =

Answer 6

nhanh len cai nao

Answer 7

hi

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