Question

Tính bằng 2 cách:

a) -5 ( 32 -36 ) + ( 31 - 39)

b) -2 ( 15 -27 ) -4 ( 12 -8 )

Answer 1

a) cách 1 :

\(-5\left(32-36\right)+\left(31-39\right)=-5.\left(-4\right)+\left(-8\right)=12\)

cách 2 ;

\(-5\left(32-36\right)+\left(31-39\right)=-5.32-\left(-5.36\right)+\left(-8\right)=-160-\left(-180\right)+8=12\)

b) cách 1 

\(-2\left(15-27\right)-4\left(12-8\right)=-2.\left(-12\right)-4.4=24-16=8\)

cách 2:

\(-2\left(15-27\right)-4\left(12-8\right)=-2.15-\left(-2.27\right)-4.12-4.\left(8\right)=-30-\left(-54\right)-48-\left(-32\right)=8\)