Đáp án:
Giải thích các bước giải:
Câu 1 a, x+1/2 + x-1/2 = x+1+x-1/2 = 2x/2 = x b, 9x-2/2xy - 5x-4/2xy = 9x-2-5x+4/2xy = 4x+2/2xy = 2x+1/xy Câu 2 a, 3+7x/x^2-1 + -2/x+1 = 3+7x/(x+1).(x-1) + -2.(x-1)/(x+1).(x-1) = 3+7x-2x+2/(x+1).(x-1) = 5/x-1 b,7/x - x/x+6 + 36/x^2+6x = 7.(x+6) - x^2 + 36/x.(x+6) = 7x + 42 - x^2 + 36/x.(x+6) = [ - (x^2) + 2.x.(7/2) - 49/4 + 90,25]/x.(x+6) = [- (x-7/2)^2 + 9,5^2]/x.(x+6) = (9,5+x-7,2).(9,5-x+7,2)/x.(x+6) = (2,3+x).(16,7-x)/x.(x+6)
