171k views
1 vote
Given f(x) = -2x² - 5x+3

2.1 Determine the x-intercept of f (3)

2.2 Determine the equation of the axes of symmetry of f (2)

2.3 Determine the range of f (2)

2.4 The graph g is obtained by reflecting graph f in the x-axis then translating it 4 units to the right. Determine the equation of graph g, in the form g(x)= a(x+p)² + q (3) ​

1 Answer

3 votes

Sure! Let’s solve these problems one by one.

2.1 To determine the x-intercepts of f, we need to find the values of x when f(x) = 0. So we need to solve the equation -2x² - 5x + 3 = 0. Using the quadratic formula, we get that x = (-(-5) ± √((-5)² - 4(-2)(3))) / (2(-2)). This simplifies to x = (5 ± √(49)) / (-4). So the x-intercepts are (5 - √(49)) / (-4) and (5 + √(49)) / (-4).

2.2 The axis of symmetry of a parabola in the form f(x) = ax² + bx + c is given by the formula x = -b / (2a). In this case, a = -2 and b = -5, so the axis of symmetry is x = -(-5) / (2(-2)) = 5/4.

2.3 The range of a quadratic function in the form f(x) = ax² + bx + c is determined by its vertex. The x-coordinate of the vertex is given by the formula x = -b / (2a), which we already calculated to be 5/4. The y-coordinate of the vertex is given by f(5/4) = -2(5/4)² - 5(5/4) + 3 = -25/8 - 25/4 + 3 = -25/8 - 50/8 + 24/8 = -51/8.

Since a < 0, the parabola opens downwards and the vertex is the highest point on the graph. Therefore, the range of f is (-∞, -51/8].

2.4 Reflecting the graph of f in the x-axis means that we change the sign of the y-coordinates. This is equivalent to replacing f(x) with -f(x). So the equation of the reflected graph is -f(x) = 2x² + 5x - 3.

Translating this graph 4 units to the right means that we replace x with (x - 4). So the equation of the translated graph is g(x) = 2(x - 4)² + 5(x - 4) - 3. Expanding this expression, we get g(x) = 2x² - 16x + 32 + 5x - 20 - 3 = 2x² - 11x + 9.

So the equation of g in the form g(x) = a(x + p)² + q is g(x) = 2(x - (-11/4))² + (9 - (121/8)).

User Terry Harvey
by
8.7k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories