Solution:
Given that,
The angle Johnny holds his pen on paper creates a linear pair
Angles in a linear pair are supplementary angles
Two angles are supplementary, when they add up to 180 degrees
The measure of one angle is 13x + 7
The measure of the second angle is one less than twice the first angle
Therefore,
Measure of second angle = twice the first angle - 1
Measure of second angle = 2(13x + 7) - 1
Measure of second angle = 26x + 14 - 1
Measure of second angle = 26x + 13
Therefore,
Measure of first angle + measure of second angle = 180
13x + 7 + 26x + 13 = 180
39x + 20 = 180
39x = 180 - 20
39x = 160
x = 4.1
Thus value of x is 4.10
