Answer:
x = 35
Explanation:
First, we need to add the angles on a straight line and subtract them by 180 (because angles on a straight line adds up to 180)
56 + 51 = 107
180 - 107 = 73
Now that we have found the angle of y, we can find the angle of x now. Because angles in a triangle adds up to 180, we have to add 72 and 73 now.
72 + 73 = 145
And now subtract it from 180
180 - 145 = 35
So x = 35