10 questions · Form 4 Mathematics Bab 1: Quadratic Functions and Equations in One Variable
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Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. For the quadratic function f(x) = -2x² + 8x - 5, what type of turning point does the graph have?
Answer: B
Since the coefficient of x² is negative (a = -2 < 0), the parabola opens downwards and has a maximum turning point.
2. Which of the following quadratic equations has roots 0 and 4?
Answer: C
Factorising x² - 4x = 0 gives x(x - 4) = 0, which yields roots x = 0 and x = 4.
3. Which of the following is a quadratic expression in one variable?
Answer: C
A quadratic expression in one variable has a single variable with a highest exponent power of 2. Option C satisfies this condition.
4. Determine the equation of the axis of symmetry for the function f(x) = 2x² - 12x + 9.
Answer: C
The formula for axis of symmetry is x = -b2a. Here, a = 2, b = -12. So x = --122 × 2 = 124 = 3.
5. Solve the quadratic equation 2x² - 7x + 3 = 0.
Answer: A
Factorising: (2x - 1)(x - 3) = 0 => 2x - 1 = 0 or x - 3 = 0. Roots are x = 12 and x = 3.
6. A rectangle has a length of (x + 4) cm and a width of (x - 1) cm. If the area of the rectangle is 36 cm², form a quadratic equation in general form.
Answer: B
Area = length × width => (x + 4)(x - 1) = 36 => x² + 3x - 4 = 36 => x² + 3x - 40 = 0.
7. What are the x-intercepts of the graph f(x) = 2x² - 8?
Answer: B
Set f(x) = 0 => 2x² - 8 = 0 => 2x² = 8 => x² = 4 => x = ±2. The x-intercepts are (-2, 0) and (2, 0).
8. Find the roots of the quadratic equation x² - 5x + 6 = 0.
Answer: B
Factorising gives (x - 2)(x - 3) = 0. Therefore, the roots are x = 2 and x = 3.
9. Given that the quadratic function f(x) = x² - bx + 16 has its axis of symmetry at x = 4, find the value of b.
Answer: A
Axis of symmetry x = --b2 × 1 = b2. Setting b2 = 4 yields b = 8.
10. Given f(x) = ax² + bx + c, if b = 0, what can be concluded about the graph?
Answer: C
When b = 0, the axis of symmetry equation x = -b2a becomes x = 0, which is the y-axis.