Answer:
A
Step-by-step explanation:
We have the expression:
![-4ab](https://tex.z-dn.net/?f=-4ab)
And we want to find its sign given that a>0 and b<0.
Notice that the expression is already negative since we have -4.
a>0 means that a is positive. Therefore, we can ignore it since it won’t do anything.
b<0 means that b is negative. Therefore, we will have two negatives being multiplied together. Hence, this will make a positive.
Therefore, the sign of our expression will be positive.
We can see this with an example. Let a=1 (1>0) and let b=-1 (-1<0). Then:
![-4(1)(-1)=4](https://tex.z-dn.net/?f=-4%281%29%28-1%29%3D4)
So, the sign is positive.
Hence, the answer is A.
Radius is the length of the line segment from the center of the circle to an endpoint on the circle and diameter is twice the length of the radius of the circle.
Answer:
![m = (5n/4) -7](https://tex.z-dn.net/?f=m%20%3D%20%285n%2F4%29%20-7)
Step-by-step explanation:
![n = 4/5(m + 7);m\\(5)n = 4(m + 7)\\5n/4 = m + 7\\m = (5n/4)/7](https://tex.z-dn.net/?f=n%20%3D%204%2F5%28m%20%2B%207%29%3Bm%5C%5C%285%29n%20%3D%204%28m%20%2B%207%29%5C%5C5n%2F4%20%3D%20m%20%2B%207%5C%5Cm%20%3D%20%285n%2F4%29%2F7)