Question

Va rog ajutati-ma!
ex spune asa:
a) ab+bc,daca a + b= 52 si c=10
b) ac-bc,daca a-b=31si c=5
c)a,daca ab+ac=42 si b+c=21
d) a,daca ab+ac+a=1765 si b+c=10
si ex asta!
a) daca a=7,b+c=15 si b-c=7,calculati ab+ac si ab-ac
b) daca a=7 si b+c+d=70,calculati ab+ad
c) daca a=3 si b+c+d=30,calculati 3a+2(ab+ac+ad)
va rog sa ma ajutati!

Answer 1

b)ac+bc=c(a+b)=5×31=155  
c)ab+ac=42, a(b+c)=42, a=42/21=2, a=2
d)ab+ac+a=1765, a(b+c+1)=1765, a=1765/10+1=1765/11=160.45