Rút gọn các phân thức sau:
Bài 1: Rút gọn các phân thức sau:
1) 20x^2y^2/15xy^7,
2) 25x^4y^7/40x^5y^4,
3) 45x^7y^4/18x^5y^6,
4) 15ab + 5b^2/9a^2 - b^2
5) 3x^2 - 3y^2/9x+9y,
6) m^2 - 4m + 4/ 2m - 4.
Bài 2: Quy đồng mẫu các phân thức sau:
1) 2-a/2a; 1/2,
2) 5/3; 5a - 6/3a,
3) 2x/3; 2ax + 3x/3a,
4) b/6a; 4a + 3b^2/18ab; x/9b,
5) x/4a; 6a - 5bx/20ab; a-1/10b,
6) 5/3; 5x-1/3(x+1),
7) 1-x/2x+1; 1/2,
8) 7/5; 7a - 31/5a - 15,
9) 3/b-1; 7-b/2b - 2
10) 2/3a; 1/2a - 2; a - 4/6a^2 - 6a
1) 20x^2y^2/15xy^7,
2) 25x^4y^7/40x^5y^4,
3) 45x^7y^4/18x^5y^6,
4) 15ab + 5b^2/9a^2 - b^2
5) 3x^2 - 3y^2/9x+9y,
6) m^2 - 4m + 4/ 2m - 4.
Bài 2: Quy đồng mẫu các phân thức sau:
1) 2-a/2a; 1/2,
2) 5/3; 5a - 6/3a,
3) 2x/3; 2ax + 3x/3a,
4) b/6a; 4a + 3b^2/18ab; x/9b,
5) x/4a; 6a - 5bx/20ab; a-1/10b,
6) 5/3; 5x-1/3(x+1),
7) 1-x/2x+1; 1/2,
8) 7/5; 7a - 31/5a - 15,
9) 3/b-1; 7-b/2b - 2
10) 2/3a; 1/2a - 2; a - 4/6a^2 - 6a