Answer: 12 and 8
Step-by-step explanation:
there not
Answer:
Step-by-step explanation:
6x + 10y = 12
-20x - 10y = 30
-14x = 42
x = -3
4(-3) + 2y = -6
-12 + 2y = -6
2y = 6
y = 3
(-3, 3)
Answer:
3 and 9.5
Step-by-step explanation:
divide 6/2 which is 3, and 19 by 2 which is 9.5. plot those on the line.
Answer: b) 6
Step-by-step explanation:
Given : The illuminance of a surface varies inversely with the square of its distance from the light source.
i.e. for d distance and l luminance , we have
, where k is constant. (1)
If the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters.
From (1), we have
(2)
For the distance (d) corresponds to the illuminance to 30 lumens per square meter , we have
![d^2\times 30=k](https://tex.z-dn.net/?f=d%5E2%5Ctimes%2030%3Dk)
Put value of k , we get
![d^2\times 30=4320\\\\\Rightarrow\ d^2=\dfrac{4320}{30}=144\\\\\Rightarrow\ d^2=144\\\\\Rightarrow\ d= 12](https://tex.z-dn.net/?f=d%5E2%5Ctimes%2030%3D4320%5C%5C%5C%5C%5CRightarrow%5C%20d%5E2%3D%5Cdfrac%7B4320%7D%7B30%7D%3D144%5C%5C%5C%5C%5CRightarrow%5C%20d%5E2%3D144%5C%5C%5C%5C%5CRightarrow%5C%20d%3D%2012)
Then , the number of meters should the distance of the surface from the source be increased= 12 meters- 6 meters = 6 meters.