Answer:
9 years
Explanation:
Lucy weighs 6.6 pounds and gains 1.7 pounds per year
The expression above can be expressed mathematically as;
1.7x + 6.6
where x = number of years
Biggie weighs 12.9 pounds and gains 1 pound per year.
The expression above can be expressed mathematically as;
x + 12.9
where x = number of years
How many years will it take until the two cats weigh the same amount?
1.7x + 6.6 = x + 12.9 (Solve for x)
1.7x - x = 12.9 - 6.6
0.7x = 6.3
x = 6.3 / 0.7 = 9 years