For a number to be divisible by 11, the difference between the sum of the digits in odd positions and even positions must be divisible by 11.

To check for divisibility by 7, you can double the last digit and subtract it from the rest of the number.

Unlimited liability for all partners is a significant disadvantage, as partners can be personally responsible for business debts.

The polynomial x^2 - 9 can be factored as (x - 3)(x + 3).

Non-Euclidean geometry explores geometries where the parallel postulate of Euclidean geometry does not hold, leading to different properties and structures.

In a general partnership, all partners typically have equal management rights unless otherwise agreed.

All statements are true; simple interest is calculated only on the principal, while compound interest is calculated on the total amount including interest.

All of the mentioned methods can be used to solve a quadratic equation.

Since 18 = 2 × 9, being a multiple of 9 is necessary for a number to be a multiple of 18.

The passage mentions that a potential drawback of digital sum is that it may lead to oversimplification of data, which can be problematic.

All polygons are defined as closed figures formed by a finite number of line segments.

In a regular polygon, all sides and all interior angles are equal.

An isosceles triangle is defined as having at least two sides that are equal in length.

Similar triangles have equal corresponding angles, but their sides are in proportion, not necessarily equal.

The roots of the polynomial can be found by factoring it as (x-2)(x-3) = 0, giving roots 2 and 3.

A number is divisible by 11 if the difference between the sum of the digits in odd positions and the sum of the digits in even positions is 0 or a multiple of 11.

To solve for x, add 9 to both sides and then divide by 3: 3x = 9, thus x = 3.

Solving the inequality gives 3x < 9, thus x < 3.

The first multiple of any number is indeed the number itself, while the other statements are false.

A number is divisible by 10 if it ends in 0.

All listed methods are valid techniques for solving systems of linear equations.

All listed methods are valid for solving systems of linear equations.

In base 8, 15 is represented as '17' (1*8 + 7).

The equation y = x^2 - 4 is non-linear because it involves a variable raised to a power greater than one.

A Fibonacci sequence cannot be expressed as a linear function; it is defined recursively.

In a geometric sequence, the ratio between consecutive terms is constant, not the difference.

A regular polygon is defined as a polygon with all sides and angles equal, and it cannot be concave; it must be convex.

The graph of a quadratic function is a parabola, not a straight line.

A circle is defined as a round shape with no corners.

In a geometric progression, the terms are numeric and follow a specific ratio; thus, non-numeric terms do not form a valid GP.