Topic content:
Calculation and simplification (4 points for each question, 16 points in total)
Subtopic 1: (1)
Subtitle 2: (2)
Subtopic 3: (3)
Subtitle 4: (4) When and when, find the value of algebraic expression.
Best answer:
Subtopic 1: (1) 8
Subtitle 2: (2)
Subtopic 3: (3) - 2x+11
Subtitle 4: (4) - 12
Answer analysis:
Solution:
(1)、
(2)、
(3)、
(4)、
Because, so
Upper formula
Substitute, into the above formula,
simple form
Analysis: Topics 1 and 2 examine the addition, subtraction, multiplication and division power of rational numbers, and the operation of absolute values. It is a simple question.
Subtitles 3 and 4 examine the addition and subtraction of integral expressions, add absolute values, and pay attention to symbols when doing questions. Subtitle 4 should also be simplified to the minimum before evaluation.
Test core:
Definition of rational number: rational number is the general name of integer and fraction. All rational numbers can be transformed into fractions.