Did your explanation include the following?
Some polynomial equations have complex solutions.
Therefore, complex solutions cannot be found by graphing the related system or function in the Cartesian (x-y) plane.
Polynomial functions with all complex solutions do not have x-intercepts, and the related system of equations will not intersect.
If one is to choose among given choices and the order is not important, we use the concept of combination. First, we calculate for the sample space or number available since there is a total number of 12 electives and a student may choose 2 out of them.
S = 12C2
That is "the sample space is equal to combination of 12 taken 2". The answer to this is equal to 66.
Next, we determine the number of outcomes. The equation will be,
O = (5C1) x (3C1)
That is "outcome is equal to combination of 5 taken 1 times combination of 3 taken 1". This is equal to 15. The probability is equal to,
P = O/S
Substituting,
P = (15/66) = 0.227270
The answer to this item is the third choice.
The ratio can be written in parts as shown below;
Then, 60 can be divided as shown below;
25kg:35kg
