In which situation would you use the equation 5y = 25?

The equation 5y = 25 represents a linear equation in one variable. You would use this equation when determining a linear relationship because it can be manipulated to find the value of y by isolating it on one side. By dividing both sides of the equation by 5, you obtain y = 5, indicating a straightforward relationship where for every increase or decrease in the variable, there is a consistent and direct change in y. This linearity is characteristic of equations where the highest power of the variable is one, and they form a straight line when graphed.

In contrast, the other situations presented do not apply to this equation: calculating probability involves ratios and likelihoods rather than linear equations, the area of a circle is determined by the formula A = πr², which is not linear in nature, and solving a quadratic equation typically involves an equation with a degree of two, indicative of its parabolic relationship.