Answer: John is 18 now
Step-by-step explanation:
If his age 5 years ago was half of his age 8 years from now, the equation can show that doubling that age will be equal to his current age plus 8 years.
2(x-5) = x + 8 . diistribute
2x - 10 = x + 8 Subtract x from both sides 2x -x +10 = x-x +8
x -10 = 8 . Add 10 to both sides . x -10 +10 = 8 + 10 simplify.
x = 18
Check:
18-5=13, 18+8= 26 . 13 is half of 26. True.