$\lim_{x \to 4} \frac{x^3 - 64}{x^2 - 16} \\\\= \lim_{x \to 4} \frac{x^3 - 64}{(x + 4)(x - 4)} \\\\=\lim_{x \to 4} \frac{(x^2 + 4x + 16)(x - 4)}{(x + 4)(x - 4)} \\\\= \lim_{x \to 4} \frac{(x^2 + 4x + 16)}{(x + 4)} \\\\= (16 + 16 + 16) / 8\\= 48 / 8\\= 6$

8 0

3 years ago

Ted practices two types of swimming styles for a total of 50 minutes every day. he spends 20 minutes more practicing the breast

cluponka [151]

Answer:

see below

Step-by-step explanation:

butterfly = x minutes

breast = y minutes

total is 50 minutes

breast stroke = butterfly +20

Part A

x+y = 50

y = x+20

Part B

Substitute the second equation into the first

x+ (x+20) = 50

2x+20 = 50

2x+20-20 = 50-20

2x = 30

2x/2 = 30/2

x = 15

y = x+20

y = 20+15

y = 35 minutes

35 minutes on the breast stroke

Part C

45 minutes on the butterfly is not reasonable

We only have a total of 50 minutes

50-45 = 5

But he spend more time on the breast stroke ( 20 minutes more), but if he spend 45 minutes on the butterfly, he would have to spend less on the breast stroke.

4 0

3 years ago

The graph of f(x)=2^x+1 passes through the points (-1 , 1) and (3 , 16).

Svetach [21]

Answer:

Please check the explanation.

Step-by-step explanation:

Rebecca's ERROR

Rebecca wrongly used the formula to calculate the average rate of change from x = -1 to x = 3.

She should have used the correct formula to calculate the average rate of change from x = -1 to x = 3 which is:

Average rate = [f(3) - f(-1)] / [3 - (-1)]

But, she reversed the formula.