Five million,three hundred twenty five thousand, six hundred three, and seven hundred twelve thousandths. hope this helps im 90 percent sure thats how you write it.
The answer is the first one!
Third side = (10x + 2 ) - (5x + 2x + 9)
third side = 10x + 2 - 7x - 9
third side = 3x - 7
answer
third side = 3x - 7