Question

Calculati numarul x,stiind ca a-b=6 si:
a)x+3•a-3•b=20
b)x•a-x•b+9a-9b=654
c)7•a-7•b+x=55
d)13+x-(5•a-5•b)=2011
Dau coroana! :)

Answer 1

a) x+3*a-3*b=

x+3(a-b)=20

x+3*6=20

x+18=20

x=2

b) x*a-x*b+9a-9b=654

x(a-b)+9(a-b)=654

x*6+9*6=654

6x=654-54

6x=600

x=100

c) 7*a-7*b+x=55

7(a-b)+x=55

7*6+x=55

x=55-42

x=13

d) 13+x-(5a-5b)=2011

13+x-[5(a-b)]=2011

13+x-5*6=2011

x=2011-13+30

x=2028