bài 1 :
a, 8x² - 6x = 2x.( 4x - 3 )
b, 64 - x² - y² = 2xy
64 - x² - y² - 2xy = 64 - ( x² + 2xy + y² )
= 64 - ( x+y)²
= 8² - (x+y)²
= ( 8+x+y).(8-x+y)
c, x²-7x+10 = x² - 2x - 5x + 10
= ( x²-2x)-(5x-10)
= x(x-2) - 5(x-2)
= (x-2)(x-5)
bài 2 :
a, x(x-1)-x²+2x = 5
x² - x -x² + 2x = 5
⇒ x = 5
b, 2x³ - x² + 2x - 1 = 0
( 2x-1)+(2x³-x²) = 0
( 2x-1)+x²(2x-1) = 0
( 2x-1)+x²(2x-1) = 0
(2x-1)(1+x²) = 0
2x -1 =0 ⇒ x= 1/2
1+x² =0 ⇒ x = ± √ -1