Factorization exercises 4m²-n²= 0.81a²-0.04b²= 2x²-8= A-A cubic= 1-x quartic power=

Factorization exercises 4m²-n²= 0.81a²-0.04b²= 2x²-8= A-A cubic= 1-x quartic power=

This is the result of the 4-n-n-\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\(1 + x) (1-x)
If the left side of equation 4x's Square - (m-n) x + 1 = 0 is a complete square, then M is equal to-----
Because the left side of 4x & # 178; - (m-n) x + 1 = 0 is a complete square
So - (m-n) = - 4 or - (m-n) = 4
So m = 4 + N, or M = - 4 + n
The formula of encounter problem and pursuit problem
Encounter: (speed a + speed b) * time = distance
Catch up: (a speed - B speed) * time = distance
How many factorization questions
1.x²-3x+2=
2.4x²-10x+6=
3.2011²-2010²=
1.x²-3x+2=(x-1)(x-2)
2.4x²-10x+6=(2x-2)(2x-3)
3.2011²-2010²=(2011+2010)(2011-2010)=4021
Let the equation 2Y & # 178; - 3y-12 = 0 form a complete square, and the equation is
A. (Y & # 178; + 3 / 2) &# 178; = 28 / 8
B. (y-178; - 3 / 2) & 178; = 38 / 8
c. (y-178; - 3 / 4) & 178; = 105 / 16
D. (y-178; - 3 / 4) & 178; = 201 / 6
2y²－3y=12
2[y²－(3/2)y＋(3/4)²]=12＋2×(3/4)²
[y－(3/2)]²=105/16
Select [C]
C
This unit is not good at learning, so we need to find a positive solution
Topic: can we catch up with Xiao Ming?
Lecture: lianjiang middle school: Li Jijie
Textbook: Grade 7 5.7 of Beijing Normal University Edition
Teaching purpose:
With the help of "line diagram", the quantitative relationship in complex problems is analyzed
Be able to solve the problems of meeting and chasing in real life with the equation of one variable and one degree
Cultivate students' ability to analyze and solve problems
Teaching focus: using equation to solve practical problems
Teaching difficulty: be able to draw "line diagram" and analyze the equivalent relationship in the journey
Teaching process:
Import:
Students! How many meters is your home from the school? How many minutes do you need to go to school? (call students to answer and write on the blackboard), so how fast do you usually go to school?
(purpose: let students transform from practical problems in life to mathematical problems)
Question 1: can you tell the relationship among distance, time and speed?
(can say: distance = speed × time) (blackboard)
Question 2: how to express the unit of speed? Today, we will apply this equivalent relationship to practical problems and see how to solve it?
New course:
1. A and B are 40 km apart. A and B set out at the same time in opposite directions. It is known that a's speed is 20 km / h and B's speed is 15 km / h. how many hours later will a and B meet? (projection)
Question 1: do you understand "Xiangxiang walking"?
Demonstration: let two students come to the stage to demonstrate the scene, and ask the students to bring the question: can you draw a line diagram according to the demonstration? \
Question 2: can you find out the equivalent relationship between the two students during the demonstration
(route a + route B = distance)
(time spent by Party A = time spent by Party B)
Question 3: can you set up the unknown quantity according to the equivalent relation and list the equation?
2. The distance between a and B is 40 km. A and B set out at the same time in the same direction. It is known that a's speed is 20 km / h and B's speed is 15 km / h. how many hours can a catch up with B? (projection)
Question 1: do you understand "going in the same direction"?
Demonstration: let two students come to the stage to demonstrate the scene, and ask the students to bring the question: can you draw a line diagram according to the demonstration? \
Question 2: can you find out the equivalent relationship between the two students during the demonstration
(distance between a and B + distance between B = distance between a and b)
(time spent by a chasing B = time spent by B walking)
Question 3: can you set up the unknown quantity according to the equivalent relation and list the equation?
Consolidation exercises:
The students study the situational examples in the book by themselves, then discuss them in groups of four, and the teacher finds out the problems during the inspection
Tips: (1) Xiao Ming walked five minutes first, so how many meters is the distance between Xiao Ming and his father?
(2) Draw a line diagram and find out the equivalent relationship
On one hand:
Complete the discussion exercises in the book and communicate with students in groups
The teacher gave a hint:
1. How many hours does the back team catch up with the front team?
2. How far did the liaison go when the back team caught up with the front team?
Summary:
Fill in the blanks below
1. Distance = ×
2. Encounter problem: the distance a takes + the distance b takes =
3. Pursuit problem: the distance of the former + the distance between the two =
If (x + y) 2 = 36, (X-Y) 2 = 16, find the value of XY and X2 + Y2
∵ (x + y) 2 = 36, (X-Y) 2 = 16, ∵ x2 + 2XY + y2 = 36, ① x2-2xy + y2 = 16, ② ① - ② get 4xy = 20, ∵ xy = 5, ① + ② get 2 (x2 + Y2) = 52, ∵ x2 + Y2 = 26
The root of equation (2x radical 3) (3x + radical 5) = 0 is
(2x radical 3) (3x + radical 5) = 0
2X = radical 3 or 3x = - radical 5
X1 = root 3 / 2 x2 = - root 5 / 3
400m circular runway
A 560 M / min, B 250 m / min
Q: how many minutes will we meet?
Is there a lack of conditions?
Solution: Party A and Party B will meet in X minutes
(560+250)X=400
Factorization
(x-1)(x-2)(x-3)(x-4)-120
(x-1)(x-2)(x-3)(x-4)-120
=(x-1)(x-4)(x-2)(x-3)-120
=(x²-5x+4)(x²-5x+6)-120
=(x²-5x+4)(x²-5x+4+2)-120
=(x²-5x+4)²+2(x²-5x+4)-120
=(x²-5x+4+12)(x²-5x+4-10)
=(x²-5x+16)(x²-5x-6)
=(x²-5x+16)(x-6)(x+1)
Crying and moving