No idea what the opposite of 18 is but the best way to pay attention in school is to not get distracted easily by anything like literally get everything that will distract you put aside get it far away from you otherwise you're not going to pay attention and I'm going to get distracted
Step-by-step explanation: y and x are supplementary and equal 180°. Triangles also equal 180° so subtract the two angles you know and x is 125°. 180 - 125 = 55°