Melanie: 15 years old
Kevin: 5 years old
Assume Kevin's present age is x.
That means that 3 years ago, his age would be x - 3.
Melanie's age would be 6(x - 3).
Same thing for 5 years into the future:
Kevin's age would be x + 5.
Melanie's age would be 2(x + 5).
The two equations we have here are:

By subtracting both equations, we are simplified to:
8 = -4x + 28
By solving the equation, we get x = 5.
That means that Kevin's current age is 5 years old.
Melanie's age could be calculated by substituting Kevins'.
6(x - 3) --> 6(5 - 3) --> 12
Since that was 3 years ago, you need to add 3 to 12 to get her current age.
12 + 3 = 15
Melanie's current age is 15 years old.
Answer:
I think this could be the answer- x^ +2x-15
4.7 x 10^4
or 5 x 10^4
<span>The scientific notation of 70, 030, 000. To find the scientific notation of this value </span><span><span>
1. </span>We first move the period which separates the whole number from the decimal number which is located after the numbers of the given value.</span>
<span><span>2. </span>We move it in the very recent order number which is seventy million, seven and zero.</span> <span><span>
3. </span>It becomes 7.003</span>
<span><span>4. </span>Thus we count how many moves we did from the tens to the ten million order place.</span> <span><span>
5. </span>7.003 x 10^7 </span>
Answer: 13. -12 , 14. 40 , 15. 16 , 16. 4.5
Step-by-step explanation: