Question

tinh nhanh :  3 * 7 + 3 * 5 - 2,5 * 3

Answer 1

3x7+3x5-2,5x3

=3x(7+5-2,5)

=3x9,5

=28,5

Answer 2

\(3\times7+3\times5-2.5\times3=3\times\left(7+5-2.5\right)=3\times9.5=28.5\) 

Answer 3

\(3\times7+3\times5-2,5\times3\)

\(=3\times\left(7+5-2,5\right)\)

\(=3\times9,5\)

\(=28,5\)

Answer 4

3 x 7 + 3 x 5 - 2,5 x 3 

= 3 x ( 7 + 5 - 2,5 )

= 3 x 9,5 

= 28,5