Answer:
28
Step-by-step explanation:
Cross multiply
18k = 12 x 42
18 k = 504
k = 504/18
k = 28
Answer:
-1/5
Step-by-step explanation:
Answer:
a)5
b)17
c) ?

Step-by-step explanation:

the equation is a quadratic one, and it has a positive coefficient on the leading term, meaning, is opening upwards, so it has a "burrow" for the vertex.
the minimum or lowest point for a quadratic opening upwards is, well, the vertex point :), the "x" value is the year, the "y" or f(x) value is the population, we're asked for the year, or the x-coordinate of the vertex
well