Because y varies inversely as x, therefore

where k = constant.
When x = 6, y = 2.5. Ther efore

Cross multiply.
k = 6 x 2.5 = 15
The equation is

When x = 4, obtain

Answer: a. 3.75
Answer:
It's the law of cosines
Step-by-step explanation:
law of cosines states that 
so we know that a = 7, b = 4, and alpha would be 135 degrees, so just plugging it in gets us 49+16-2*7*4*(-0.707) = 65 + 39.59 = 104.59
Answer:
D. 150 metres
Step-by-step explanation:
speed = (60) times 5/18 = 50/3
lenght of the train = (speed x time)
lenght = 50/3 times (9)
= 150 m.
Answer:
C
Step-by-step explanation:
x in the first equation because you can divide every other number in that equation by 3.