Question

daca a,b,c aparine de N si ab+ca=715,calculati 18a(5b+5c).

Answer 1

   
[tex]a,~b,~c \in N \\ \\ ab+ca = 715 ~~\Longrightarrow~~ \boxed{a(b+c) = 715}\\ \\ 8a[5b+5c] = 8a[5(b+c)]= 8a\times 5(b+c)= \\ \\ =8\times5\times a(b+c)=40\times a(b+c) = 40\times 715 = \boxed {\boxed{28600}}[/tex]