Answer:
y=mx+c
We have to find the value of m and c.
Let's substitute the value of x and y from the table.
When x=1, y=15,
15= m(1)+c
m +c= 15 ------(1)
Now substitute another set of x and y values.
When x=2, y=24,
24= m(2)+c
2m +c= 24
c= 24 -2m ------(2)
Let me rewrite the two equations so that it is clearer for you to see.
m + c= 15 -----(1)
c = 24 -2m -----(2)
subst. (2) into (1):
m+ 24-2m= 15
-m= 15-24 (bring constants to 1 side, m terms to the other)
-m= -9 (simplify)
m= 9 ( divide by -1 throughout)
subst. m=9 into (2):
c= 24 -2(9)
c= 24-18
c= 6
Thus, the equation is y=9x+6.
When the cat is 3 years old, x=3.
When x=3,
y= 9(3)+6
y= 33.
Hence, the cat is 33 years old in human years.