To isolate n you need to divide to undo the multiplication
4=-0.8n
--- -----
-0.8 -0.8
-5=n
I hope I've helped!
Answer:
x=19º
x+9=28º
7x=133º
Step-by-step explanation:
x+9+x+7x=180
9x+9=180
9x=180-9
9x=171
x=19
40 is 20% of 160, so if she saved 40$ and it was 20% off then the original price was 160$!!!
These techniques for elimination are preferred for 3rd order systems and higher. They use "Row-Reduction" techniques/pivoting and many subtle math tricks to reduce a matrix to either a solvable form or perhaps provide an inverse of a matrix (A-1)of linear equation AX=b. Solving systems of linear equations (n>2) by elimination is a topic unto itself and is the preferred method. As the system of equations increases, the "condition" of a matrix becomes extremely important. Some of this may sound completely alien to you. Don't worry about these topics until Linear Algebra when systems of linear equations (Rank 'n') become larger than 2.
