Question

If mZFDE = (3x – 15) and mZFDB = (5x + 59)", find the value of x such that ZFDE and ZFDB are supplementary.

Answer 1

You have the next measures of angles:

$m\angle\text{ZFDE}=(3x-15)$$m\angle ZFDB=(5x+59)$

And you need to find the value that makes the angles supplementary. It means that you need to find the value of x that makes that: the sum of the angles has to be 180º

$m\angle ZFDE+m\angle ZFDB=180º$

Then you have:

$(3x-15)+(5x+59)=180$

You clear the x, as follow:

$3x+5x-15+59=180$$8x+44=180$Then so, the value of x that makes that ZFDE and ZFDB are supplementary is x=17