Question

Tính nhanh a) 4x5-4x2+8   b) 2x3+9+3x3. c) 2+2x9

 

Answer 1

a) 4 x 5 - 4 x 2 + 4

= 4 x 5 - 4 x 2 + 4 x 1

= 4 x ( 5 - 2 + 1 )

= 4 x 4

= 16

b) 2 x 3 + 9 + 3 x 3

= 2 x 3 + 3 x 3 + 3 x 3

= 3 x ( 2 + 3 + 3 )

= 3 x 8

= 24

c) 2 + 2 x 9

= 2 x 1 + 2 x 9

= 2 x ( 1 + 9 )

= 2 x 10

= 20

Answer 2

a) 4 x 5 - 4 x 2 + 4

= 4 x 5 - 4 x 2 + 4 x 1

= 4 x ( 5 - 2 + 1 )

= 4 x 4

= 16

b) 2 x 3 + 9 + 3 x 3

= 2 x 3 + 3 x 3 + 3 x 3

= 3 x ( 2 + 3 + 3 )

= 3 x 8

= 24

c) 2 + 2 x 9

= 2 x 1 + 2 x 9

= 2 x ( 1 + 9 )

= 2 x 10

= 20

Đáp án đây nhé