1. Child: auntie, I'll buy a box of biscuits and a bag of milk Aunt: children, originally you can only buy a box of biscuits with 10 yuan, but it's not enough to buy another bag of milk. However, today is children's day, and biscuits are 10% off, so you'll get 80 cents for two things 2. The solution of (x + 2) ² + 6 (x + 2) + 9 = 0 is () 3. 27x & # 178; - 18x = - 3 (solving by factorization method, 4. 4 (x-3) &# 178; - x (x-3) = 0 (to be solved by factorization method, 5. (2x-1) (3x + 4) = 2x-1 (solution, by factorization method, 6. 3 (x-3) = (x-3) &, 7. If there is a number whose square ratio of the sum of 2 times and 4 is greater than 2, find this number. Let this number be X. according to the meaning of the problem, get the equation (), and solve the equation X1 = (), X2 = () 8. Try to write out a quadratic equation with one variable respectively, so that its two parts satisfy the following conditions: (1) A root is 1 and a root is - 2:; (2) One is negative and the other is between 2 and 3 9. The annual output value of an enterprise increases from 10 million yuan to 12.1 million yuan in two years Forget, the first problem is to find the unit price of milk and biscuit respectively Please answer the questions before December 11, and add more points quickly

1. Child: auntie, I'll buy a box of biscuits and a bag of milk Aunt: children, originally you can only buy a box of biscuits with 10 yuan, but it's not enough to buy another bag of milk. However, today is children's day, and biscuits are 10% off, so you'll get 80 cents for two things 2. The solution of (x + 2) ² + 6 (x + 2) + 9 = 0 is () 3. 27x & # 178; - 18x = - 3 (solving by factorization method, 4. 4 (x-3) &# 178; - x (x-3) = 0 (to be solved by factorization method, 5. (2x-1) (3x + 4) = 2x-1 (solution, by factorization method, 6. 3 (x-3) = (x-3) &, 7. If there is a number whose square ratio of the sum of 2 times and 4 is greater than 2, find this number. Let this number be X. according to the meaning of the problem, get the equation (), and solve the equation X1 = (), X2 = () 8. Try to write out a quadratic equation with one variable respectively, so that its two parts satisfy the following conditions: (1) A root is 1 and a root is - 2:; (2) One is negative and the other is between 2 and 3 9. The annual output value of an enterprise increases from 10 million yuan to 12.1 million yuan in two years Forget, the first problem is to find the unit price of milk and biscuit respectively Please answer the questions before December 11, and add more points quickly

2. X = - 53, 27x & # 178; - 18x = - 33 (9x & # 178; - 6x + 1) = 03 (3x-1) & # 178; = 0 deduce x = 1 / 34, 4 (x-3) & # 178; - x (x-3) = 0 (x-3) [4 (x-3) - x] = 0 (x-3) (3x-12) = 0, that is, 3 (x-3) (x-4) = 0. The solution is: X1 = 3; x2 = 4.5, (2x-1) (3x + 4) = 2x

2. The area of a square is 16 cm2. When the side length is increased by x cm, the square area is y cm2, then the function of Y with respect to X is____________ .
3. If the quadratic function y = x2 + C passes through the point (2,0), then when x = - 2, y=____________
2. The coordinates of the intersection of the parabola y = 4x2-11x-3 and the Y axis are_______________
3. The coordinates of the intersection of the parabola y = - 6x2-x + 2 and the X axis are___________
It is known that the base length of an isosceles triangle is 8, and the waist length is a root of the equation
4. In order to solve the problem of difficulty for people to see a doctor, the municipal government decided to reduce the price of drugs. After two successive price cuts, the price of a certain drug was reduced from 200 yuan per box to 128 yuan. The average percentage of each price reduction was calculated
The last two questions need to be processed, plus 20 points

1.y=4x+16
two
3.(0,-3)
4. (- 0.5,0) or (2 / 3,0)
5. What is the equation?
6. Suppose that the down regulation rate is X
200*(1-X)^2=128
X1 = 1.8 (rounding off), X2 = 0.2
0.2=20%
A

How to make up for Mathematics in grade two to grade three

Do more questions, think more, cultivate their interest in learning is the key. You can buy some teacher recommended materials and simulation questions to do, at this time do more, and wrong will do, so the question of naval warfare may not be a good method, but don't do something you can do, general big questions can improve faster, to quiet

Senior high school mathematics "position relationship of straight line, intersection coordinates of straight line and distance formula"
Given a vertex a (- 3,4) of △ ABC, the linear equation x + 2Y + 3 = 0 for the height on edge AB, and the linear equation 2x-3y + 6 = 0 for the height on edge AC, the coordinates of vertices B and C are obtained

The information obtained from the title is: the higher crossing point C on the edge of AB, the equation of the line AB is 2x-y + 10 = 0
The equation of line AC is 3x + 2Y + 1 = 0. ②
B (1, - 2) is obtained from equation 2 and equation x + 2Y + 3 = 0
Similarly, C (- 6, - 2)

The focal coordinate formula of ellipse
Know the equation of ellipse and find the formula of focus

Formula of distance from point to line
I remember teaching in high school. It's too long and I've forgotten. Now I need to write a program
For example, how to find the distance from a point a (a, b) to a straight line L: ax1 + by1 + C = 0? What we need is a formula
Another oblique expression is: y = KX + B, right, where k is not equal to 0, and K = TG (AI Er FA), right

The distance formula from point Po (XO, yo) to the straight line L: ax + by + C = 0 is: | axo + BYO + C = 0 | divided by the sum of the square of a + the square of B and then quadratic; the oblique formula of point Po (XO, yo) with slope k is: y-yo = K (x-xo); y = KX + B is oblique

Excuse me, does anyone know the point line distance formula, line line line distance formula, line plane distance formula, point plane distance formula in high school mathematics

Distance between point and line: make a vertical line from point to line, and the length of the vertical line is the distance between point and line. Let the point be a (m, n); the straight line be y = KX + B. then the slope of the vertical line is - 1 / K, and the vertical line is y = - 1 / KX + N-km

The parabola y = - X2 (is the square of x)
The minimum distance between a point on a parabola and a straight line 4x + 3y-8 = 0 is?

Method 1
Let (x, - x ^ 2) be the point of the parabola y = - x ^ 2,
So the distance from the point to the line 4x + 3y-8 = 0 is:
|4x-3x^2-8|/5＝|3x^2-4x+8|/5
=|3(x-2/3)^2+20/3|/5
So the minimum value is: (20 / 3) / 5 = 4 / 3
Method 2
Let 4x + 3Y + M = 0 be the parallel tangent to 4x + 3y-8 = 0
It is connected with parabola and equal to 0 by discriminant
Solve m, and convert the distance from point to line into the distance between two parallel lines

Know the equation of a point and circle of a straight line and the chord length, how to find the equation of a straight line

Let y = K (x-x0) + Y0 and (x0, Y0) be a point on the line
Substituting it into the equation of circle, we get the quadratic equation of X
If the two roots are X1 and X2, then the points (x1, Y1), (X2, Y2) are the intersection points
Its distance = chord length. From this, we can get the equation of K and solve it

Given the two points on the circle and the chord length of a given line L intersecting the circle, how to find the equation of the circle

It's easy to build a coordinate system: suppose that the known chord length is 2S, now take the midpoint of the chord as the origin, and take the line L as the x-axis to establish a rectangular coordinate system. In this coordinate system, the known two points are (m, n) and (P, q), where s, m, N, P, q are known real numbers
Since the middle perpendicular of the string must pass through the center of the circle, so the center of the circle is on the y-axis. Let the center of the circle be (0, b), and then the radius of the circle be r. then the equation of the circle can be expressed as: X & # 178; + (y-b) &# 178; = R & # 178;, where B and R are unknowns, and there are many letters. Please make sure to make it clear, and then you can start to do the problem
First of all, connect the center of the circle and the intersection of the straight line and the circle to form a right triangle. The length of the hypotenuse is r, and the lengths of the two right angles are s and B respectively
b²=r²-s² ①
Then, (m, n) and (P, q) are substituted into the set equation
m²+（n-b）²=r²
→ m²+（n-b）²= p²+（q-b）² ②
p²+（q-b）²=r²
Simplify formula 2 to get b = (M & # 178; + n & # 178; - P & # 178; - Q & # 178;) / 2 (n-q). The right side of the equal sign is a constant. For convenience, let's use C instead
So there is b = C, B & # 178; = C & # 178; ③
Finally, we substitute formula 3 into Formula 1, where C & # 178; = R & # 178; - S & # 178;, where C and s are constants, R is solved, R is solved, B is solved, so the equation is solved
P. S. if the topic gives a straight line with specific equation, chord length of specific value and two points of specific coordinate, it can't do as above, because the topic has given a rectangular coordinate system, but the relationship between each value is the same as above. Just use your brain, use various geometric formulas you have learned, and work out the above three relationships