Câu hỏi của Bích Nguyệtt

Question

tìm x

a)1/2x. (x^2 - 4) = 0

b) (x+2 )^2 - ( x- 2) (x+ 2) = 0

꧁༺β£ɑℭƙ £❍ζʊꜱ༻꧂ · Accepted Answer

a. $\frac{1}{2}x\left(x^2-4\right)=0$

$\frac{1}{2}x\left(x-2\right)\left(x+2\right)=0$

* $\frac{1}{2}x=0$

$x=0$

* $x-2=0$

$x=2$

* $x+2=0$

$x=-2$

b. $\left(x+2\right)^2-\left(x-2\right)\left(x+2\right)=0$

$\left(x+2\right)\left(x+2\right)-\left(x-2\right)\left(x+2\right)=0$

$\left(x+2\right)\left(x+2-x+2\right)=0$

$\left(x+2\right).4=0$

$x+2=0$

$x=-2$Câu trả lời: a. $\frac{1}{2}x\left(x^2-4\right)=0$

$\frac{1}{2}x\left(x-2\right)\left(x+2\right)=0$

* $\frac{1}{2}x=0$

$x=0$

* $x-2=0$

$x=2$

* $x+2=0$

$x=-2$

b. $\left(x+2\right)^2-\left(x-2\right)\left(x+2\right)=0$

$\left(x+2\right)\left(x+2\right)-\left(x-2\right)\left(x+2\right)=0$

$\left(x+2\right)\left(x+2-x+2\right)=0$

$\left(x+2\right).4=0$

$x+2=0$

$x=-2$

Nguyễn Phạm Thái Bảo · Answer

(=) (x+2)[(x+2) - (x-2)] = 0

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

(=) 4(x+2) = 0

=> x+2 = 0

=> x = -2Câu trả lời: (=) (x+2)[(x+2) - (x-2)] = 0

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

(=) 4(x+2) = 0

=> x+2 = 0

=> x = -2

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