Junior high school mathematics, ask for the answer, thank you, junior high school mathematics, ask f

I'm also going to play soy sauce and give a quadratic function over the origin and point (-1 2, -1 4), and the distance from the other intersection point of the x-axis to the origin is 1, then we can see that the quadratic function crosses the point (0,0), the point (-1 2,-1 4), and the point (-1,0) or the point (1,0).

Let the quadratic function be: y=ax 2+bx+c (0,0) c=0

The quadratic function is: y=ax 2+bx

In the case of points (0,0), points (-1 2,-1 4), and points (-1,0), substituting y=ax 2+bx

That is: -1 4=1 4a-1 2b 0=a-b with *1 2 - can be solved: a=1, b=1

y=x^2+x

In the case of the function passing the point (0,0), the point (-1 2,-1 4), and the point (1,0) is substituted by y=ax 2+bx

That is: -1 4=1 4a-1 2b 0=a+b can be solved with *1 2 + to obtain: a=-1 3, b=1 3

y=-1/3x^2+1/3x

I don't know if I can help you!!

And then there's the question you asked, -b 2a, which is about finding the axis of symmetry, which has something to do with this question.

And you can also calculate the point (0,0) according to the axis of symmetry, and the point (-1,0) or the point (1,0).

You can find the axis of symmetry x=1 2 or x=-1 2 and then replace it with a for b or b for a

Then substitute the points (-1 2, -1 4) into the quadratic function.

It can be found directly, which is simpler than the above steps, and this method is very convenient and fast for doing this kind of quadratic function problems.

This quadratic function passes through the origin and (-1 2, -1 4).

Let y=ax 2+bx

1/4a-1/2b=-1/4

a=2b-1

ax^2+bx=0

x(ax+b)=0

x=0,x=-b/a

b/a=1a=-b2b-1=-b

b=1/3，a=-1/3

y=-1/3x^2+1/3x

b/a=-1

a=bb=1，a=1

y=x^2+x

This is a good solution, but it is easier to solve it with two roots.

1) The vertex of the parabola y=2(x+3 2) is (-3 2,0), the vertex of the parabola is (-3 2,0), and the opening direction and shape are the same as the parabola y=-8x, and the analytical formula is y=-8(x+3 2).

2) Translate 5 units to the left to get y=-8(x+13 2) If you have any questions, please ask; If you are satisfied, thank you!

1) y=-8x -3 2(2)y=-8(x-5) -3 2 you beginner, the basic concept is.

A simple way to do this is symmetry with respect to the x-axis x is invariant -y instead of y, symmetry with y-axis symmetry with -x instead of x and y unchanged about origin symmetry with -x instead of x -y because (x,y) the point coordinates of symmetry with respect to the x-axis are (x,-y), while (x,y) the point coordinates of symmetry with respect to the y-axis are (-x,y) ,x,y) the point symmetrical with respect to the origin is (-x,-y) The function image is made up of an infinite number of (x,y) points that satisfy the known equation.

Solution: (1) Because the sum of the lengths of the two diagonals of the diamond is exactly 60cm, and one of them is x, the length of the other diagonal can be obtained as 60-x

And because the diagonal lines of the diamond are bisected perpendicular to each other.

Therefore, the area of the rhombus is s=4 (1 2) (x 2) [60-x) 2]=1 2(60x-x 2).

2)s=1/2(60x-x^2)=-1/2(x^2-60x+900-900)=-1/2(x-30)^2+450

Therefore, when x=30cm, the diamond-shaped kite has the largest area s, which is 450.

1、s=（1/2）x(60-x)=-(1/2)x^2+30x

2. The formula will not be used for formula: when x=-(b 2a), the maximum value of s: (4ac-b 2) 4a

s = 60x-x2 (squared) = - (x2-60x+30*30-30*30) = - (x-30)(x-30)+900

So when x=30, the area s is up to 900

Who told you that the DE vertical BC ah?

1 If m 0, n 0, then.

The root number is m of n

The absolute value of m n.

The root number of the M n2 equation is 1-x=2, squared, 1-x=4, x=-3

The root number 2-2 of the 3 root number 2-2 can also be simplified, that is: ( 2-2) 2

1. Positive and negative m

2、x=-3

3. The problem is not very clear, is there a screenshot?

The length of the arc AD = 90 r 180

Whereas the length of the arc AD is 2 2

90 r 180 = 2 2 , the solution is r = 2ad = 2od = 2 2 =2, and ab is the tangent of o, oa ab, i.e. oab = 90°, point c is the midpoint of ob, ac = 1 2 bc = oc = 2

The unary quadratic equation with 2 and 2 as the root can be (x-2)(x-2)=0 and the general formula is: x-(2+ 2)(x=2 2)=0,

The analytic formula of a quadratic function is generally determined by three points.

If there is only one point (1,2).

Let y=ax +bx+c, as long as 2=a+b+c is satisfied.

Let a=1, b=2, c=-1

It could be y=x +2x-1

Simplified: 5 times in 2015 plus 5 times in 2014, and 2014 times in common factor 5 is extracted again, resulting in 5 times in 2014 (5 1), so it is divisible by 6.

Does this still have to be asked? After subtracting, of course, it is a multiple of 5 or 10 points, and it is impossible to have a single digit of 3, 6, 9