Question

Folosind factorului comun, calculeaza i) a x c - c x b daca a - b =24 si c = 3 ii) 7 x a + 9 x b + 2 x c daca a + b = 43 si b+c =15

Answer 1

i) a - b = 24 si c = 3
a × c - c × b =
= c × (a - b) =
= 3 × 24 =
= 72

ii)
a + b = 43 si b + c = 15

7 × a + 9 × b + 2 × c =

= 7 × a + 7 × b + 2 × b + 2 × c =

= 7 × (a+b) + 2 × (b + c) =

= 7 × 43 + 2 × 15 =

= 301 + 30 =

= 331