Question

ukł. równań:

1) {a+b=12,5

{80%b+120%a=13

2) {x+y=600

{5%x+20%y=10%·600

plisss pomocyy potrzebne na dzisiaj;c

Answer 1

1)

 a+b=12,5

 80%b+120%a=13

 

a = 12,5-b

0,8a+1,2b = 13

 

a = 12,5-b

0,8(12,5-b)+1,2b = 13

 

a = 12,5-b

10-0,8b+1,2b = 13

 

a = 12,5-b

0,4b = 13-10

 

a = 12,5-b

0,4b = 3 /:0,4

 

a = 12,5-b

b = 7,5

 

a = 12,5-7,5

b = 7,5

 

a = 5

b = 7,5

 

2)  

x+y=600

5%x+20%y=10%·600

 

x = 600-y

0,05x+0,2y = 0,1·600

 

x = 600-y

0,05(600-y)+0,2y = 60

 

x = 600-y

30-0,05y+0,2y = 60

 

x = 600-y

0,15y = 60-30

 

x = 600-y

0,15y = 30 /:0,15

 

x = 600-y

y = 200

 

x = 600-200

y = 200

 

x = 400

y = 200