Problem 80 - Beginning and Intermediate Algebra

Question

Solve. $$m^{1 / 2}=-7$$

Step-by-Step Solution

Answer

The given equation is \(m^{1/2} = -7\). To solve for m, square both sides of the equation: \((m^{1/2})^2 = (-7)^2\). This simplifies to \(m = 49\).

Step 1: Write down the equation

The given equation is: \(m^{1/2} = -7\)

Step 2: Eliminate the square root

In order to eliminate the square root, we can square both sides of the equation. This will give us: \((m^{1/2})^2 = (-7)^2\)

Step 3: Simplify the equation

After squaring both sides, we are left with: \(m = 49\) Therefore, the value of m that satisfies the given equation is \(m = 49\).

Key Concepts

Square Roots

Square roots are quite fascinating and central to many mathematical concepts. When we talk about the square root of a number, we refer to a value that, when multiplied by itself, gives the original number. For instance, the square root of 9 is 3, because 3 times 3 equals 9. In algebraic terms, the square root of a number \(m\) is often represented as \(m^{1/2}\).

In the original exercise, we begin with \(m^{1/2}\), implying we're dealing with the square root of \(m\). The equation presented, \(m^{1/2} = -7\), might initially seem odd because it implies that a square root is negative, which is typically not possible with real numbers. This highlights an important rule in mathematics: the principal square root should always be positive in the real number system. Understanding these core concepts will help with recognizing when solutions are real or involve complex numbers.

Squaring Both Sides

To solve equations involving square roots, one common technique is squaring both sides. This method helps eliminate the square root to directly work with more straightforward expressions. When you square a number or variable, you multiply it by itself. For our equation \(m^{1/2} = -7\), squaring both sides gives us \((m^{1/2})^2 = (-7)^2\).

By squaring the square root \(m^{1/2}\), we effectively cancel out the root, returning the variable to its original form \(m\). Simultaneously, on the right side, \((-7)^2\) results in 49, which is positive because squaring any real number, whether positive or negative, results in a positive outcome. Squaring both sides is a powerful tool, but remember to check if the solutions make sense, especially with negative numbers under square roots.

Algebraic Manipulation

Algebraic manipulation refers to the various techniques used to rearrange and solve equations. Here, after squaring both sides, we derived the equation \(m = 49\). It's a simple step from here, as the equation has been neatly isolated with \(m\) already on one side.

Algebraic manipulation often involves operations such as addition, subtraction, multiplication, division, and factoring, to simplify expressions or solve for unknowns. In this scenario, it was straightforward after squaring both sides because the equation directly provided \(m = 49\).

Understanding algebraic manipulation is key in mathematics, as it allows us to extract and interpret solutions. It gives us the ability to transform complex problems into more manageable steps through logical operations and transformations, ensuring that each step maintains the equation's balance.