I started by labeling the right angle (Angle C) 90º. Next, I wrote down everything in one equation.
2x + 90 + 3x - 20 = 180º (180 degrees in a triangle)
Next, I add 20 on both sides.
2x + 90 + 3x = 200º
I combine like terms (2x and 3x)
5x + 90 = 200º
I subtract 90 from both sides.
5x = 110º
Divide 110 by 5 to get x.
x = 22
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For problem two, I label all the angles I know.
49º + 80º + r = 180º
I add 80 and 49.
129º + r = 180º
I subtract 180 and 129 and get 51º, which is your angle for R.
For angle X, you know that angle R plus angle X equals half of a circle, which is 180º
We know from before that 129º is 180º without R, so X is 129º
I hope this helps! Let me know if I'm wrong!
