Answer:
a = kb
Step-by-step explanation:
"a is directly proportional to b" is expressed as a = kb, where k is the "constant of proportionality."
If the 5 scores have a mean of 8, then their total sum would be 8*5 = 40
Now if one score if added (let's call this score x), there are 6 scores and the mean changes to 9, thus:
(40 + x)/6 = 9
40 + x = 54
x = 14
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.
Answer: Kara should have written the proportion in step 1 as;
Start Fraction 12 Over 72 End Fraction = Start Fraction 14 Over x End Fraction (that is 12/72 = 14/x)
Step-by-step explanation: The two similar triangles are given with the following dimensions;
Triangle VXW with side VW = 12 and side VX = 14. Also Triangle ZXY with side YZ = 72 and side XZ = x.
For two triangles to be similar, then there must be a similarity ration that is consistent with all sides in both triangles. This means if in the first triangle a side measures 1 unit and the similar side in the other triangle measures 5 units, then the ratio of similarity of corresponding sides shall be ratio 1 : 5. So for every corresponding side in the second triangle the measurement shall be times five of the side that corresponds in the first triangle.
Therefore, in triangle VXW and triangle ZXY, the corresponding sides are as follows;
VX = ZX
VW = ZY
XW = XY
What Kara did was as follows;
VX/ZY = VW/ZX
Which translates to 14/72 = 12/x
This was a wrong calculation because the side that corresponds to VX is ZX and not ZY.
The correct step should therefore have been;
VW/ZY = VX/ZX
12/72 = 14/x (Step 1)
12x = (72) (14) {Step 2}
x = 1008/12 (Step 3)
x = 84 (Step 4)
