Giúp mik zới: a) 25x mũ 2 – 160 =9 b) ( 2x – 1) mũ 2 – ( x – 3 ) mũ 2 =0 c) ( x + 4 ) mũ 2 – ( x – 1 ) ( x + 1 )= 16 d) ( 2x – 1 ) mũ 2 + ( x+ 3 ) mũ

Đáp án + Giải thích các bước giải:

`a)`

`25x^2-160=9`

`<=> 25x^2=169`

`<=> x^2=169/25`

`<=> x = +- 13/5`

`b)`

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

`<=> (2x-1-x+3)(2x-1+x-3)=0`

`<=> (x+2)(3x-4)=0`

`<=>`  \(\left[ \begin{array}{l}x+2=0\\3x-4=0\end{array} \right.\) `<=>` \(\left[ \begin{array}{l}x=-2\\x=\dfrac{4}{3}\end{array} \right.\) 

`c)`

`(x+4)^2-(x-1)(x+1)=16`

`<=> x^2+8x+16-(x^2-1)=16`

`<=> x^2+8x+16-x^2+1=16`

`<=> 8x+17=16`

`<=> 8x=-1`

`<=> x=-1/8`

`d)`

`(2x-1)^2+(x+3)^2-5(x-1)(x+1)=0`

`<=> 4x^2-4x+1+x^2+6x+9-5(x^2-1)=0`

`<=> 5x^2+2x+10-5x^2+5=0`

`<=> 2x+15=0`

`<=> 2x=-15`

`<=> x=-15/2`