\(15,5\cdot20,8-3,5\cdot9,2-15,5\cdot9,2+3,5\cdot20,8\)

\(=15,8\left(20,8-9,2\right)+3,5\left(-9,2+20,8\right)\)

\(=15,5\cdot11,6+3,5\cdot11,6\)

\(=11,6\left(15,5+3,5\right)=11,6\cdot19=220,4\)

Ta có: \(15,5.20,8-3,5.9,2-15,5.9,2+3,5.20,8\)

\(=\left(15,5.20,8+3,5.20,8\right)-\left(3,5.9,2+15,5.9,2\right)\)

\(=20,8\left(15,5+3,5\right)-9,2\left(3,5+15,5\right)\)

\(=395,2-174,8=220,4\)

=20,80.(-15,5-15,5)+9,2.(15,5.3,5)

=-644.8+499.1

=-145.7

xin lỗi

kết quả là -360 nhé bn

\(-15,5.20,8+3,5.9,2-15,5.9,2+3,5.20,8\)

\(=-15,5\left(20,8+9,2\right)+3,5\left(9,2+20,8\right)\)

\(=\left(-15,5\right).30+3,5.30\)

\(=30.\left(-12,5\right)\)

\(=-375\)

\(-15,5.20,8+3,5.9,2-15,5.9,2+3,5.20,8\)

\(=20,8.\left(-15,5+3,5\right)+9,2.\left(-15,5+3,5\right)\)

\(=\left(-15,5+3,5\right).\left(20,8+9,2\right)\)

\(=\left(-12\right).30\)

\(=-360\)

Vậy : \(-15,5.20,8+3,5.9,2-15,5.9,2+3,5.20,8=-360\)

\(-15,5.20,8+3,5.9,2-15,5.9,2+3,5.20,8\)

= \(20,8.\left(-15,5+3,5\right)+9,2.\left(-15,5+3,5\right)\)

= \(20,8.\left(-12\right)+9,2.\left(-12\right)\)

= \(\left(20,8+9,2\right).\left(-12\right)\)

= \(30.\left(-12\right)\)

= \(-360.\)

Chúc bạn học tốt!

= -15,5 .( 20,8 - 9,2) + 3,5 . (9,2+20,8)

=-15,5 . 11,6 + 3,5 .30

=-179,8+105

=-74,8

\(-15,5.20,8+3,5.9,2-15,5.9,2+3,5.20,8\)

\(=-15,5\left(20,8+9,2\right)+3,5\left(9,2+20,8\right)\)

\(=\left(9,2+20,8\right)\left(-15,5+3,5\right)\)

\(=30.\left(-12\right)=-360\)

A) -15,5 x 20,8 +2,5 x 9,2 -15,5 x 9,2 + 3,5 x 20,8

=-15,5 x 20,8 + 2,5 x 9,2 + -15,5 x 9,2 +3,5 x 20,8

=[20,8x(-15,5+3,5)]+[9,2x(2,5+-15,5)]

=[20,8x(-12)]+[9,2x(-13)]

=-249,6+-119,6

=-369,2

a) -369,2

b) -7