Is y=x and y=x-7 a solution

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

The volume of the sun is approximately 1 × 10^18 cu km, while the volume of jupiter is approximately 1 × 10^15 cu km. which of the following is true? a. the volume of jupiter is approximately one thousand times the volume of the sun. b. the volume of jupiter is approximately one hundred times the volume of the sun. c. the volume of the sun is approximately one thousand times the volume of jupiter. d. the volume of the sun is approximately one hundred times the volume of jupiter.

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?