A direct variation is a mathematical relationship between two variables that can be expressed by an equation in which one variable is equal to a constant times the other. In other words, a direct variation is where
.
In answer a,
, so it is a direct variation.
In answer c,
, so it is a direct variation.
In answer d,
, so it is a direct variation,
Only answer b is left, which means the answer must be 'b'.
We also know 'b' is the answer because it cannot be expressed as <span>
. Instead, it is expressed as </span>
, which is not the same thing and is therefore not a direct variation.
Hope I helped, and let me know if you have any questions :)
2a + 3b = 6 --> Equation 1
5a + 2b = 4 --> Equation 2
Equation 1 * 5 --> 10a + 15b = 30
Equation 2 * 2 --> 10a + 4b = 8
Equation 1 - Equation 2 --> 11b = 22 --> b = 2
Sub b=2 in Equation 1 (or 2, either works):
2a + 3b = 6
2a + 3(2) = 6
2a + 6 = 6
2a = 0
a = 0
b = 2, a = 0
Answer:
20
Step-by-step explanation:
12 + 3 = 15
15+5=20
Answer:
Precambrian period
Step-by-step explanation:
Since the Great oxidation period = 2.4 Billion years ago era = Precambrian period.
Micro-fossils attributed to cyanobacteria are abundant during the Proterozoic that came later 2,5 billion years ago and ended 540 million years ago,