The way I figured this one out was saying that if it takes 2lbs to stretch it to 12 inches and 5lbs to stretch to 18 inches that means that 3 additional pounds = 6 inches. Therefore, each additional pound is 2 inches. We know already that with 2 lbs it was 12 inches in length and we can also say that 2 lbs = 4 inches. So subtract 4 from 12 and you end up with the answer of 8 inches.
Y=-2x+0 haahahaha hope i helped i think
Example: 
We can see that there is more than one number with the variable x, therefore, we say they're ''like terms'' and because of that they can be summed. We do this with all of the other numbers with similar variables. If no numbers with similar variables are left, like 4a, you don't do anything but write them as they are. You can also see that 8 and 9 can also be summed because neither of them has a variable, therefore they're similar.
In this step, you just do the operation with the numbers and keep the same variable.


since there are not more numbers similar in variables, this operation is done.

No it is not a prime number
Answer:
41 and 77
Step-by-step explanation:
x: his age the first time he went to space
y: his age the second time he went to space
the second time he went to space he was 5 years younger than twice the age when he went his first time, then:
y = 2x - 5
the sum of both ages is 118, then:
x + y = 118
If you replace y = 2x - 5 in x + y =118:
x + 2x - 5 = 118
3x = 123
x = 41
replacing x:
41 + y = 118
y = 118 - 41
y = 77
so when he was 77, he was 5 years younger than twice 41 ( 41*2 = 82 => 82 - 5 =77)