а²+3ab/a-2b - 7ab-4ab/a-2b= a²+3ab-7ab+4ab/a-2b= a²/a-2b
или
а²+3ab/a-2b - 7ab-4bv/a-2b= a²+3ab-7ab+4bv/a-2b=a²-4ab+4bv/a-2b
а²+3ab/a-2b - 7ab-4ab/a-2b= a²+3ab-7ab+4ab/a-2b= a²/a-2b
или
а²+3ab/a-2b - 7ab-4bv/a-2b= a²+3ab-7ab+4bv/a-2b=a²-4ab+4bv/a-2b