Answer:


Step-by-step explanation:
<h3><u>Question 1</u></h3>
The intervals on which a <u>quadratic function</u> is positive are those intervals where the function is above the x-axis, i.e. where y > 0.
The zeros of the <u>quadratic function</u> are the points at which the parabola crosses the x-axis.
As the given <u>quadratic function</u> has a negative leading coefficient, the parabola opens downwards. Therefore, the interval on which y > 0 is between the zeros.
To find the zeros of the given <u>quadratic function</u>, substitute y = 0 and factor:

Apply the <u>zero-product property</u>:


Therefore, the interval on which the function is positive is:
- Solution: 1 < x < 4
- Interval notation: (1, 4)
<h3><u>Question 2</u></h3>
The intervals on which a <u>quadratic function</u> is negative are those intervals where the function is below the x-axis, i.e. where y < 0.
The zeros of the <u>quadratic function</u> are the points at which the parabola crosses the x-axis.
As the given <u>quadratic function</u> has a positive leading coefficient, the parabola opens upwards. Therefore, the interval on which y < 0 is between the zeros.
To find the zeros of the given <u>quadratic function</u>, substitute y = 0 and factor:

Apply the <u>zero-product property</u>:


Therefore, the interval on which the function is negative is:
- Solution: -2 < x < 4
- Interval notation: (-2, 4)