"-y (less than or greater than sign) 136" translates into two separate inequalities:
-y < 136 and -y > 136.
You want to solve for y in each case. To do this, multiply each inequality by "-1" and then immediately change the direction of the inequality sign.
For example: -1(-y < 136) => y > -136.
Using the sinusoidal function, it is found that the temperature will be below 0ºC between May and August.
<h3>
What is a Sinusoidal function?</h3>
- A sinusoidal function is a function that depends on a trigonometric function, having peaks according to the period and amplitude given by this function.
The function for the average monthly temperature, in m months after January, is given by:

Working with elementary angles, we have that:





From this, we have that it becomes negative after March, and positive before September, removing the middle two options.
Now, we have to test for April and May, that is, m = 4 and m = 5, hence:


Negative only in May, hence the temperature will be below 0ºC between May and August.
To learn more about sinusoidal function, you can take a look at brainly.com/question/18055768
1.) (x - 4)(x + 1) = 0
x^2 + x - 4x - 4 = 0
y = x^2 - 3x - 4
2.) (x - 2)(x - 6) = 0
x^2 - 6x - 2x + 12 = 0
x^2 - 8x + 12 = 0
since the function has a maximum point the leading coefficient is negative.
Therefore, required equation is y = -3x^2 + 24x - 36
3.) a(x + 3)^2 = ax^2 + 6ax + 9a
since the y intercept is at y = 18 => 9a = 18 => a = 2
Therefore, required function is y = 2x^2 + 12x + 18