CÂU 15. ĐÁP ÁN A. TA CÓ 32X + 50X -2 8X + 18X 2 2 2 2= + - + = + - +

16.2x 25.2x 2 4.2x 9.2x 4 .2x 5 .2x 2 2 .2x 3 .2x= + - + = + - + = . 4 2x 5 2x 4 2x 3 2x 2 (4x 5 4 3) 8 2x