Question

2 ) Tìm x
(x-3)^2-(x-2)(x-8)=12
(2x+5)^2=(3x-8)^2

Answer 1

 

(x-3)^2-(x-2)(x-8)=12

<=>x²-6x+9-(x²-10x+16)=12

<=>x²-6x+9-x²+10x-16=12

<=>4x-7=12

<=>4x=19

<=>x=\(\frac{19}{4}\)

 

(2x+5)^2=(3x-8)^2

<=>(2x+5)²-(3x-8)²=0

<=>(2x-5-3x+8)(2x-5+3x-8)=0

<=>(3-x)(5x-13)=0

<=>3-x=0 hoặc 5x-13=0

<=>x=3 hoặc x=\(\frac{13}{5}\)

Answer 2

sửa lại :

(x-3)^2-(x-2)(x-8)=12

<=>x²-6x+9-x²+10x-16=12

<=>4x-7=12

<=>4x=19

<=>x=19/4

(2x+5)^2=(3x-8)^2

<=>(2x+5)²-(3x-8)²=0

<=>(2x+5-3x+8)(2x+5+3x-8)=0

<=>(11-x)(5x-3)=0

<=>11-x=0 hoặc 5x-3=0

<=>x=11 hoặc x=3/5