Notice from the graph that angles AGE and BGH are supplementary. This means that their sum is 180˚. Therefore, to find the value of x, we must solve the equation (5x – 7) + (3x + 19) = 180
To do this, we must isolate the variable on one side by undoing the equation. We do this by first combining like terms. In this case, the variable values, and the non–variable values.
***Before doing this, make it all addition by converting – (+7) into + (–7)
So our equation is 5x + 3x + –7 + 19 = 180.
5x + 3x = 8x and –7 + 19 = 12 Now we have 8x + 12 = 180
This is a simple equation. We undo the addition by subtracting 12 from both sides: 8x + 12 – 12 = 180 – 12 8x = 168
Then, we undo the multiplication by dividing 8 by both sides: 8x ÷ 8 = 168 ÷ 8 x = 21 We can check to, as (5 • 21 – 7) + (3 • 21 + 19) = 180
Now, we can easily figure out the measurements of your angles: angle AGE = 5 • 21 – 7 = 98 So the measure of angle AGE = 98˚
Upon observing the diagram more closely, you can see that angle AGE and GHD are congruent, meaning they have the same measurements. This means that if angle AGE = 98˚, then so does angle GHD.