Aboy is x years old. his sister is twice as old he is. the sum of their age is 27, how old is the boy?

The boy is 9

9x2=18

18+9=27

9

18

27

36

45

54

63

72

81

Twice as older so if he was 9 she would be TWICE AS older so like 3 x 9 which equals  27

to plot points   for x just start at the origin (middle) and go to the left however many times it say(if the number is a positive) if the number is a negative then go right however many times it says if it is 0 go nowhere

now keep you pencil there and go up however many times it says on y(if it is positive) if it is negative then go down however many times it says. if it says 0 go nowhere.

you have just plotted a point! now when you finish plotting all of them connect them with a ruler

plot each point as (-3, 7), (0,4), (3,1), (8,-4)   in the parenthesis on the left of the comma is x and the right is y.