Autonomous inquiry

1.( 1)x+ 1, 1, a-b, Party A-Party B.

② Algebraic expressions, letters.

2.( 1) is not equal to

(2) negative 2 is not equal to negative 2

(3)2

Self-attempt

1.c2.b3.d4. 1.5。 (1) 8x, 80% of x.

(2)a+b，a-b