Axis question

[Brokerhenry]

Hello: I have a question that I hope someone could help me answer. I am using Excel 2007. Say I have Y axis values that go from 0 to 10 and I have X axis values that go from 0 to 17, and the graph that I drew is a straight line graph. If I am given a Y axis number of say 6.5, how do I find the corresponding point on the X axis using Excel?

thank you.

[pb71]

Add a linear trendline. With the chart selected, select Layout - Analysis - Trendline - Linear Trendline. This will display the y = mx + c (m =gradient, c = y-axis intercept) equation on the chart for the series.

Select the Trendline on the chart - Format Trendline - Display Equation on chart.

See attached example.

[Brokerhenry]

Thank you pb71 for your response. The graph that you drew is exactly what I needed. So, how do I choose point 6.5 on the Y axis and how do I find the corresponding value on the X axis?

Thank you.

[teylyn]

Use the formula provided by the trendline to calculate it. In this case, the formula is

y = 3x + 2

So, if x=6.5, plug it into the formula: 3*6.5 + 2 will give you the Y axis value.

To find a Y value for a given x, just reverse the formula

x = (y-2) / 3

Plug it in: (6.5 -2) / 3 is the formula to calculate X where Y = 6.5

[Brokerhenry]

I see it now. Thanks for all your help.