28 is the least common multiple. To find the least common multiple, you look through the numbers both 4 and 7 go into. The smallest of those number is the least common multiple, or LCD.
From left to right, top to bottom: 1 and 2 are neither, 1 and 2 are neither, 1 and 2 are neither, 1 and 2 are cooresponding angles, 1 and 2 are alterante interior angles.
The formula is given in the middle. You are supposed to insert the value of x into this formula to find the value of y (like in the first given example):
