Question

Tìm x , biết :

a) (x-2)² - ( x-3 )(x+3) = 6

b) 4(x - 3)² - (2x-1)(2x+1) = 10

c) 4(x-4)² - (x-2)(x+2) = 6

d) 9( x+1 )² - (3x-2)(3x+2) =10

Answer 1

a) ( x - 2 )² - ( x - 3 )( x+ 3) = 6

( x² - 4x + 4 ) - ( x² - 9 ) = 6

x² - 4x + 4 - x² + 9 = 6

-4x + 13 = 6

-4x = -7

x = 7/4

Answer 2

b: =>4(x^2-6x+9)-4x^2+1=10

=>4x^2-24x+36-4x^2+1=10

=>-24x+37=10

=>-24x=-27

=>x=9/8

c: =>4x^2-32x+64-x^2+4=6

=>3x^2-32x+62=0

hay \(x=\dfrac{16\pm\sqrt{70}}{3}\)

d: =>9x^2+18x+9-9x^2+4=10

=>18x+23=10

=>18x=-13

=>x=-13/18