12 x 78 - 24 x 19
= 12 x 78 - 12 x 2 x 19
= 12 x 78 - 2 x 19
= 12 x 78 - (2 x 9)
= 12 x 78 - 38
= 12 x (78 - 38)
= 12 x 40
= 480
12x78-24x19
=12x78-12x(2x19)
=12x78-12x38
=12x(78-38)
=12x40
=480
12 x 78 - 24 x 19
= 12 x 78 - ( 12 + 12 ) x 19
= 12 x 78 - 12 x 19 + 12 x 19
= 12 x ( 78 - 19 + 19 )
= 12 x 78
= 936
\(12x78-24x19\)
\(=12x78-12x2x19\)
\(=12x78-2x19\)
\(=12x78-38\)
\(=12x\left(78-38\right)\)
\(=12x40\)
\(=480\)
Chúc bạn học tốt Ngo khanh huyen !
12x78-24x19=12x78-2x12x19
= 12x78-12x38
= 12x (78-30)
= 600
