All angles in a triangle add to 180. So, we must add all those expressions together and set them equal to 180.
2x+3+4x+2+2x-1=180
Now we combine like terms (2x+4x+3x is 8x, 3+2-1 is 4)
8x+4=180
Now subtract 4 from both sides (4-4 is 0, 180-4 is 176)
8x=176
Now divide both sides by 8.
x=22.
Now substitute 22 wherever you see x in each expression.
2x+3 = 2(22)+3 = 44+ 3 = 47
4x+2 = 4(22)+2 = 88+2 = 90
2x-1 = 2(22)-1 = 44-1 = 43
So the final answer is A=47°, B=90°, C=43°
To check, add these numbers together and see if they equal 180.
90+43+47 is 180, so the answers are correct.