Đáp án:

 

Giải thích các bước giải:

 `\text{1)}`

$\text{$(2x-3)^{2}$ - ( 2x-3).(2x+3) = 0 }$

$\text{(2x-3). [ ( 2x-3) - (2x+3)] = 0 }$

$\text{(2x-3).(-6) = 0}$

$\text{-12x+18 = 0}$

$\text{-12x = -18}$

$\text{x = $\frac{3}{2}$ }$

2)

$\text{$(3-4x)^{2}$ - 3.(4x-3) = 0 }$

$\text{$(4x-3)^{2}$  - 3.(4x-3) }$

`\text{(4x-3).(4x-3 - 3) = 0}` 

TH1:

$\text{4x-3=0}$

$\text{4x=3}$

$\text{x =$\frac{3}{4}$ }$ 

TH2:

`\text{4x- 6=0}`

`\text{4x=6}`

`\text{x = $\frac{3}{2}$}`

3)

`\text{(x-5).(x+5)-15x+75=0}`

`\text{(x-5).(x+5)-15(x-5)=0}`

`\text{(x-5).(x+5-15)=0}`

TH1:

`\text{x-5=0}`

$\text{x=5}$

TH2:

`\text{x-10=0}`

`\text{x=10}`

#hoc247

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