If A is directly proportional to C and B is directly proportional to C, prove that each of the following is directly proportiona
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Answer:
See attached
Step-by-step explanation:
When there is a lot of repetitive calculation to do, I like to let a spreadsheet or graphing calculator do it. The attached shows a spreadsheet that computes all the values you're asked to find.
For a linear equation in standard form, ax +by = c
- the x-intercept is: c/a
- the y-intercept is: c/b
- the slope is: m = -a/b
Of course, the slope-intercept form of the equation is ...
y = (slope)·x + (y-intercept)
and the values of the various points on the graph can be computed from that equation.
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You will note that the last two equations describe the same line.
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<em>Note on spreadsheet formulas</em>
When you put the formulas into the spreadsheet, make sure to fix the column number or row number of the values you're computing, as appropriate. For example, the y-values in the different columns always use the slope from the slope column (fixed), the y-intercept from that column (fixed), and the x-value from the top row (fixed). If you make the cell references relative instead of fixed, you will get wrong answers.
