Which of the following pairs of lines are perpendicular? y=3x-4 and y=-1/2 x-5
y=1/2 and y=2x-1
y=x and y=-x
Please help with this. 60 points for this!

Recall that the owner of a local health food store recently started a new ad campaign to attract more business and wants to know if average daily sales have increased. historically average daily sales were approximately $2,700. the upper bound of the 95% range of likely sample means for this one-sided test is approximately $2,843.44. if the owner took a random sample of forty-five days and found that daily average sales were now $2,984, what can she conclude at the 95% confidence level?