One way of determining the answer is by substituting the values to the equation. It is done as follows:
A. (4,1)
<span>y = 3x - 1
</span>1 = 3(4) - 1 = 11 -------> not equal
B. (2,5)
<span>y = 3x - 1
</span>5 = 3(2) - 1 = 5 --------> equal
C. (4,3)
<span>y = 3x - 1
</span>3 = 3(4) -1 --------------> not equal
D. (0, -3)
<span>y = 3x - 1
-3 = 3(0) -1 = -1 ---------> not equal</span>
A, C. A is obviously correct because it’s the e same thing and C you combine like terms (2n+n=3n,2+4=6,=3n+6) it’s not B because it’s not 18, it’s not D because you’d get 3n+18 and it’s not E because you’d get 3n+12, meaning the only correct answers are A and C
This is a combination problem. The approach to this is by using the nCr method, where n is the number of total objects and r is the number of success. For example, if you want to get 3 red out of the total 4, then that would be 4C3. That means,
4C3 = 4!/3!(4 - 3)! = 4 ways
If you want to get 2 green out of the total 6, then that would be 6C2. That means,
6C2 = 6!/2!(6-2)! = 15 ways
Therefore, there are a total of 4+15 = <em>19 ways</em>.
