VN 3. Tìm x a) (x + 2)(x + 3) – (x – 2)(x + 5) = 6; b) (3x + 2)(2x + 9) – (x + 2)(6x + 1) = (x + 1) – (x – 6). VN 4. Cho a + b + c = 12, ab + bc + ca
VN 3. Tìm x a) (x + 2)(x + 3) – (x – 2)(x + 5) = 6; b) (3x + 2)(2x + 9) – (x + 2)(6x + 1) = (x + 1) – (x – 6). VN 4. Cho a + b + c = 12, ab + bc + ca = 47 … Đọc tiếp