2 LOG22X − 14 LOG4X + = 3 0 ⇔ 2 LOG22 X − 7 LOG2X + = 3 0LOG 1⇔ LOG2 X = 3 HAY 2X = 2 ⇔ X = 23 = 8 HAY X = 212 = 21 11 1 1 1X − X + X = − + =2 2 4 3 2( ( 2 )I = ∫ X X − DX = ∫ X − X + X DX = 5 4 3 1( )

1) - DAP AN MON TOAN THOT 2010
Toán DAP AN MON TOAN THOT 2010

1) 2 log

22

x − 14 log

4

x + = 3 0 ⇔ 2 log

22

x − 7 log

2

x + = 3 0

log 1

⇔ log

2

x = 3 hay

2

x = 2 ⇔ x = 2

3

= 8 hay x = 2

12

= 2

1 1

1 1 1 1

x − x + x = − + =

2 2 4 3 2

( 1) ( 2 )

I = ∫ x x − dx = ∫ x − x + x dx =

5 4 3 1

( )