( 315+372 ) . 3 + ( 372 + 315 )

= (315+315) + (372+372) . 3

= 630 + 744 . 3

= 1374 . 3

= 4122

\(B=\frac{\left(315+372\right).3+\left(372+315\right).7}{26.13+74.14}=\frac{315.3+372.3+372.7+315.7}{26.13+74.14}=\frac{315.\left(7+3\right)+372.\left(7+3\right)}{26.13+74.14}=\frac{3150+3720}{26.13+74.14}\)

đến đấy bó tay

\(\frac{\left(315+372\right).3+\left(372+315\right).7}{26.13+74.48}\)

\(=\frac{\left(315+372\right).\left(3+7\right)}{\left(26.13\right)+\left(74.48\right)}\)

\(=\frac{687.10}{39+3552}\)

\(=\frac{6870}{3890}=\frac{687}{389}\)

\(\left(2061+4809\right):1374\)

\(=6870:1374\)

\(=5\)

[(315+372).3+(372+315).7]: (26.13+74.14)[(315+372).3+(372+315).7]: (26.13+74.14)

=[(7+3)(315+372)]:(2.13.13+2.7.74)=[(7+3)(315+372)]:(2.13.13+2.7.74)

= (10.687):[2(13.13+7.74)]= (10.687):[2(13.13+7.74)]

=(10.687):(2.687)=(10.687):(2.687)

=6870:1374=6870:1374

=5

=5 tich ik mk giai ro rang ra cho 

\(\frac{\left(315+372\right).3+\left(372+315\right).7}{26.13+74.14}=\frac{\left(315+372\right).10}{2.\left(13.13+74.7\right)}=\frac{687.10}{2.687}=5\)

\(\frac{\left(315+372\right).3+\left(372+315\right).7}{26.13+74.14}\)

\(=\frac{\left(315+372\right)\left(3+7\right)}{26.13+74.13+74}\)

\(=\frac{687.10}{13\left(26+74\right)+74}\)

\(=\frac{6870}{13.100+74}=\frac{6870}{1300+74}\)

\(=\frac{6870}{1374}\)

\(=4511,5\) nhé bạn