Step-by-step explanation:
step 1. break into 2 shapes: a rectangle of sides 3 and 4. a triangle of sides (x - 3), 4, and y.
step 2. y = 4sqrt(2) (definition of a 45° triangle)
step 3. note: sqrt is the square root.
step 4. x - 3 = 4 (definition of a 45° triangle)
step 5. x = 7 (add 3 to both sides).
