A quadratic function is defined by \( f(x) = -2x^2 + 12x + k \), where \( k \) is a constant. The graph of \( y = f(x) \) has a zero at \( x = 7 \). (a) Determine the value of \( k \). (1 mark) (b) Determine the coordinates of the turning point of the graph of \( y = f(x) \). (2 marks) (c) Determine the other zero of the function. (1 mark)
Mathematical Methods · Unit 1 · Surds and quadratic functions · Quadratic functions
Determine turning points and zeros of quadratic functions, with and without technology.
Practise this objective
AI-marked practice questions tied to QCAA mark schemes for this exact LO. Free to start.
Start free practicePractice questions for this objective
Full questions, answers and worked solutions unlock when you start a free practice session.
A parabola has the equation \( y = ax^2 + bx + 18 \) and passes through the point \( (3, 0) \). The parabola has a turning point at \( x = 2 \). (a) Determine the values of \( a \) and \( b \). (3 marks) (b) Hence determine the \( y \)-coordinate of the turning point. (1 mark)
Consider the quadratic function $f(x) = 2x^2 - 8x + 3$. (a) Determine the coordinates of the turning point. [1 mark] (b) Determine the $x$-intercepts (zeros) of the function, correct to 2 decimal places. [2 marks]
Consider the quadratic function $f(x) = 2x^2 - 8x + 5$. (a) Determine the coordinates of the vertex (turning point) of the graph of $f(x)$. [1 mark] (b) Determine the zeros of $f(x)$, giving your answer in exact form. [2 marks]
For the quadratic function $f(x) = 2x^2 - 5x - 3$, determine the coordinates of the vertex (turning point).
A quadratic function is given by \( f(x) = 2x^2 + px + q \), where \( p \) and \( q \) are constants. The function has a turning point at \( (3, -7) \). (a) Determine the values of \( p \) and \( q \). (2 marks) (b) Determine the \( x \)-coordinates of the zeros of \( f(x) \), correct to two decimal places. (2 marks)
Determine the x-coordinates of the turning point and the zeros of the quadratic function f(x) = 2x² - 8x + 6.