answer: x=36
explanation: in the corner of (2x+18)°, it would be 90° as it is a right angle, 90-18=72 72/2=36, putting it into the equation 2(36)+18=90°. for (3x+6), putting 36 as x 3(36)+6=114° since every 3-sided triangle and a line with another line crossing through has angles that add up to 120°, if you add up 90 and 24 you get 114°, 120-114=6. if you add 6 to the 114° from the (3x+6)° equation you also get 120°, therefore x=36
