Whats 1ab + 2cd = 43 ?

Plz which expression is equivalent to the expression below?

The population of a small rural town in the year 2006 was 2,459. the population can be modeled by the function below, where f(x residents and t is the number of years elapsed since 2006. f(t) = 2,459(0.92)

Which equation can be solved to find x the measure of jk in the apex