5與x的差的比x的2倍大1的方程是__________.

當(dāng)x = ________時,代數(shù)式與的值相等.

若代數(shù)式的值是1,則k = _________.

若x = -3是方程3(x - a) = 7的解,則a = ________.

x = 3和x = - 6中,________是方程x - 3(x + 2) = 6的解.

某件商品連續(xù)兩次9折降價銷售,降價后每件商品售價為a元,則該商品每件原價為(   ) A.0.92a           B.1.12a             C.        D.

已知:當(dāng)b = 1,c = -2時,代數(shù)式ab + bc + ca = 10, 則a的值為          (   )

  A.12                  B.6                 C.-6            D.-12

關(guān)于x的方程(2k -1)x² -(2k + 1)x + 3 = 0是一元一次方程, 則k值為 (   )

  A.0                   B.1                 C.            D.2

方程 x - 3 = 2 + 3x的解是                                        (   )

  A.-2;                 B.2;                C.-;         D.

下列等式變形正確的是                                                    (   )

  A.如果s = ab,那么b = ;             B.如果x = 6,那么x = 3

  C.如果x - 3 = y - 3,那么x - y = 0;     D.如果mx = my,那么x = y