Question

scoateti factor comun si calculati: a)-5×42+(-5)×24-(-5)×28 b)101×(-5)+202-101×(-4)+3×(-101)
c) 12×300+(-1)×(-300)-4×300+300×6

Answer 1

a ) 
-5 ( 42 + 24 - 28 ) =
-5 ( 66 - 28 ) =
-5 × 38 = -190

b)
101 × ( -5 ) + 2 × 101 - 101 × ( -4 ) + 3 × ( -101) =
101 ( -5 + 2 + 4 - 3 ) =
101 × (-2) = -202

c)
300 ( 12 + 1  - 4 + 6 ) 
300 × 15 = 4500

Answer 2

a)  -5 × 42 + ( - 5 ) × 24 - ( - 5 ) × 28  = - 190 
= ( - 5 ) × ( 66 - 28 ) =
= ( - 5 ) × 38 
= - 190 

b)  101 × ( - 5 ) + 202 - 101 × ( - 4 ) + 3 × ( - 101 ) = - 202 
= 101 × ( - 5 ) + 2 × 101 - 101 × ( - 4 ) + 3 × ( - 101 ) =
= 101 × ( - 5 + 2 + 4 - 3 ) =
= 101 × ( - 2) =
= - 202 

c)  12 × 300 + (-1) × (-300) - 4 × 300 + 300 × 6= 4 500 
= 300  ×  ( 12 + 1 - 4 + 6 ) = 
= 300 × 15 = 
= 4 500