How many questions do you can t ask, high score, this question is not very good?

Here comes the standard answer.

y=ax*+bx (a, b is constant).

1) If the car is traveling at a speed of 60 kilometers per hour, the braking distance is . If the car is driving at 80 kilometers per hour, the braking distance is meters, find the values of a and b, and determine the function relation.

2) If a herd of antelopes suddenly crosses the road 30 meters in front of a high-speed car, stops 1 meter away from the flock, and asks what the speed of the car is before braking.

Substitution, a=, b=

So, the functional relation is y=

Analysis, from the sight of the antelope, exactly 30 meters, and to stop at a distance of 1 meter from the sheep, here 1 meter, must be in front of the antelope, that is, 30-1 = 29 meters, indicating that the car can exercise up to 29 meters, substitution, and use inequality.

03x^2-10x-29000<=0

Solve the equation so that Equation = 0

Delta = 10 * 10 + 4 * 3 * 29000 = 590 * 590

x1 = 100 m-s, x2 = -29 3 m-s (rounded).

According to the equation <=0, x>-29 3 is actually x>0, x<100 meter seconds.

That is, 0 idea analysis: this topic is a program decision-making question, which is informative and miscellaneous, requiring students to read and understand carefully, collect and sort out relevant information, and use functional knowledge to answer according to the requirements of the question.

Solution: (1) Knowing from the meaning of the question, p=30+x

2) From the inscription, the sales of live crabs are (1000-10x) (30+x) yuan, and the sales of dead crabs are: 200x yuan.

So q = (1000-10x) (30+x) + 200x = 10x2 + 900x + 30000

3) Let the total profit be: l=q-30000-400x= 10x2+500x

When x=25, the total profit is the largest, and the maximum profit is 6250 yuan.

Brief analysis: function is an important content of junior high school algebra, it is with the solution of equations, the solution of inequalities and other contents, widely used, master the determination of the analytic formula of the function and the basic knowledge of the properties of the function, is the key to solve the algebra comprehensive problems.

1.Solution: (1) When x=60, y=; When x=80, y= is brought into the equation.

The solution is a= b=

Functional equation: y=

2) According to the question y=29

So 29 = solution x = 100

2.Solution: (1) Knowing from the meaning of the question, p=30+x

2) From the meaning of the title, the sales of live crabs are (1000-10x)*(30+x) yuan, and the sales of dead crabs are: 20*10x yuan.

So q = (1000-10x) (30+x) + 200x = 10x2 + 900x + 30000

3) Let the total profit be: l=q-30000-400x= 10x2+500x

10(x-25)^2+6250

When x=25, the total profit is the largest, and the maximum profit is 6250 yuan.

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Summary. 3.Substitution:

Substitution is a method of judging the solution of an inequality by substituting a specific numerical value. For example, for the inequality 2x + 1 > 5, you can first let x = 2 get 2 2 + 1 = 5, true, and then try x = 1 to get 2 1 + 1 = 3, which is not true, so the solution of x is x > Graph method: A method of judging the solution of inequality by drawing the graph corresponding to the inequality and finding the solution in the graph.

For example, for the inequality 2x + 1 > 5, you can draw a graph with the straight lines y = 2x + 1 and y = 5, and find the part of the graph that satisfies the inequality, i.e., x > 2. The above are several common methods for solving inequalities in junior high school, and you can choose the appropriate method to solve according to the specific inequality.

These days are written in the first equation and represented by a number line.

No, find the value of x, or draw a number line representation (can you send a standard list of questions) I know the format you want. Dear

It is to be solved with equations.

Requires a value of x.

Can you give the process a hassle.

Hello. Pro, the combination of numbers and shapes, looking at the graph can be directly solved.

The methods for solving inequalities in junior high schools mainly include the following:1Shift Method:

The shift-term method is a basic method of solving inequalities. Move all the calendar line unknowns to the side, move the known numbers to the side, and get the solution of the inequality by comparing the size relationships. For example, for the inequality 2x + 1 > 5, you can move 1 and 5 to the same side, and move 2x to the other side to get 2x > 4, and finally solve x > Merge the same term:

The method of merging similar terms is to combine the terms of the same kind in the inequality into a single term, thereby simplifying the solution of the inequality. For example, for the inequality 2x + 3 > x + 5, you can combine the same terms 2x and x to get 3x to get the inequality 3x + 3 > 5, which can be solved by shifting terms.

3.Substitution: Substitution is a method of judging the solution of an inequality by substituting a specific numerical value.

For example, for the inequality 2x + 1 > 5, you can first let x = 2, get 2 2 + 1 = 5, hold, and then try x = 1 to get 2 1 + 1 = 3, not true, so the solution of x is x > Graph method: Draw the pin graph corresponding to the inequality through the rotten bucket base, and find the solution in the graph to judge the solution of the inequality. For example, for the inequality 2x + 1 > 5, you can draw a graph with the straight lines y = 2x + 1 and y = 5, and find the part of the graph that satisfies the inequality, i.e., x > 2.

The above are several common methods for solving inequalities in junior high school, and you can choose the appropriate method to solve the inequalities according to the specific inequality.

The condition for continuity is that the value of the function is equal to the right to the left of the change.

That is, when x=0, the values of the two functions are equal, a=2

I will answer this question, and when you have time, I will answer it for you and explain it to you.

This question is a workbook for elementary school in the second volume of the fourth grade.

A right triangle is given in the multiple-choice question as a multiple-choice question, and the quick and correct answer requires the elimination method plus the deterministic method to select the correct answer.

The answers given are that the two right-angled sides are equal, so you just need to verify that the answers to the following options conform to the Pythagorean theorem of right-angled triangles.

Only option d matches the sum of x squared plus y squared to l squared, so d is chosen.

Hello, the answer should be d. Using the Pythagorean theorem, we can know that the maximum area of a triangle is when the two right-angled sides are equal, that is, the length of each side is equal to half of the square of the hypotenuse.