Math Problem Statement

Koordinat titik balik kurva f(x) = x^2 - 10x + 29 adalah .... and Bentuk fungsi kuadrat yang tepat untuk grafik di atas adalah ....

Solution

Let's analyze and solve the two mathematical problems shown in the image.

1. Koordinat titik balik kurva

The given quadratic function is:

f(x)=x210x+29f(x) = x^2 - 10x + 29

To find the vertex (titik balik) of the parabola, we use the formula for the x-coordinate of the vertex:

xvertex=b2ax_{\text{vertex}} = -\frac{b}{2a}

Here, a=1a = 1 and b=10b = -10. Substituting into the formula:

xvertex=102(1)=5x_{\text{vertex}} = -\frac{-10}{2(1)} = 5

Now, substitute x=5x = 5 into the function to find the y-coordinate of the vertex:

f(5)=(5)210(5)+29=2550+29=4f(5) = (5)^2 - 10(5) + 29 = 25 - 50 + 29 = 4

Thus, the vertex (titik balik) is at the point (5,4)(5, 4).

Answer: The correct option is (5,4)(5, 4).


2. Perhatikan grafik fungsi kuadrat berikut

The second question asks to identify the quadratic function that matches the given graph.

The graph shows a parabola that opens upwards with these points:

  • (3,0)(-3, 0), (1,4)(-1, -4), (1,0)(1, 0), and (0,3)(0, -3).

The general form of a quadratic function is:

f(x)=ax2+bx+cf(x) = ax^2 + bx + c

From the graph, the parabola crosses the x-axis at (3,0)(-3, 0) and (1,0)(1, 0). This means the factors of the quadratic function are (x+3)(x1)(x + 3)(x - 1), giving us the equation:

f(x)=a(x+3)(x1)f(x) = a(x + 3)(x - 1)

Expanding this:

f(x)=a(x2x3x3)=a(x22x3)f(x) = a(x^2 - x - 3x - 3) = a(x^2 - 2x - 3)

Now, to determine the value of aa, we use the point (1,4)(-1, -4). Substituting x=1x = -1 and f(x)=4f(x) = -4:

4=a((1)22(1)3)=a(1+23)=a(0)-4 = a((-1)^2 - 2(-1) - 3) = a(1 + 2 - 3) = a(0)

Since this equation doesn't provide the value of aa, I would recommend trying this again with all points

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Math Problem Analysis

Mathematical Concepts

Quadratic Functions
Parabolas
Vertex Calculation
Factoring

Formulas

Vertex formula: x_vertex = -b / (2a)
Factoring quadratic functions
General form of quadratic functions: f(x) = ax^2 + bx + c

Theorems

Parabola vertex theorem
Quadratic factoring

Suitable Grade Level

Grades 9-11