Answer:
jack (with the lower case j) is 11 years old
Step-by-step explanation:
(x - 5) + (3x - 5) = 34
x - 5 + 3x - 5 = 34
4x = 34 + 10
4x = 44
x = 11
So, jack = 11 years old.
Jack = 33 years old.
For rounding to the nearest 10, you look at the 1's place and determine if its over 5 or under 5. If it is under 5 you round down to the nearest ten, and if its over you go to the nearest ten. For 407, 7 is over 5, so it is 410.
Well, you can see in the system that they give you the expression x = 6 - y. So it's literally telling you that, well, x equals (6 - y), and therefore since they're equivalent expressions, you can substitute 6 - y for x to solve the system.