Question

a) x^2(x-1)-(x+1)(x^2-2)=1+x^2

b) x(3x+5) - (x+3)(2x-1) = x-x^2

c) (x+7)(x-2)=0

d) 2x(x-1)+( 3-x)(1-2x)=4-3x

Mong các bạn trả lời nhanh giúp mình

Answer 1

a) x\(^2\) ( x-1 ) - ( x+1 ) ( x\(^2\)-2 ) = 1 + x\(^2\)

=> x\(^3\) - x\(^2\) - x. ( x\(^2\)-2 ) + x\(^2\) - 2 = 1 + x\(^2\)

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

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

=> 2x - 2 = 1 + x\(^2\)

=> 2x = x\(^2\) + 1+2

=> 2x = x.x + 3

<=> 2x > x.x

Để 2x > x.x

=> x = 1

Nếu x = 1

=> 2x = x.x+3

=> 2.1 = 1+3 ( Vô lý )

=> Không có giá trị x nào để x\(^2\) ( x-1 ) - ( x+1 ) ( x\(^2\)-2 ) = 1 + x\(^2\)