I would recommend "Introduction to Linear Algebra," by Gilbert Strang. It is a compact but very helpful textbook reference written by a well-known MIT professor. There is a corresponding online MIT course that is free, so that's a bonus. I am currently using it to study linear algebra with no class or previous experience, and I think it does a solid job of explaining things. Each section in the book has a set of questions for you to work through, and answers to selected questions appear in an appendix at the end of the book.
Hope this helps!
The answer is 4 isn’t it?
20 possibilities based on this as a combination not a permutation, 6 nCr 3 = 20
Answer:
The player throws 127.3 ft from second base to home plate.
Step-by-step explanation:
Given:
Distance from home to first base = 90 ft
Distance from first base to second base = 90 ft
We need to find the distance from second base to home.
Solution:
Now we can assume the complete scenario to be formed as a right angled triangle with two sides given and to find the third side.
Now by using Pythagoras theorem which states that;
Square of the hypotenuse side is equal to sum of squares of other two sides.
framing in equation form we get;
distance from second base to home = 
Rounding to nearest tent we get;
distance from second base to home = 127.3 ft
Hence The player throws 127.3 ft from second base to home plate.
3s+28=85, take away 28 from both sides of the equals to give you 3s=57, divide by 3 on both side to give you s=19.