X1 is normal with mean mu and variance sigma^2. X2 is normal with mean mu and variance 2sigma^2. Consider the estimator cX1 + (1-c)X2. For what value of c is the variance minimized?

What are “like terms”? why can we only add like terms?

Eric has challenged himself to walk 24,000 steps in 4 days. if eric walks the same number of steps each day, which function represents the number of steps eric still needs to walk to reach his goal with respect to the number of days since he started his challenge? a. y = 8,000x − 24,000 b. y = -8,000x + 24,000 c. y = 6,000x − 24,000 d. y = -6,000x + 24,000

Let f(x) = 5/x and g(x)=2x2+5x. what two numbers are not in the domain of f o g