Question

Tell whether the given value of the variable is a solution of the equation.

$21-z=- 4; z=25$

Short answer

Yes, $z=25$is the solution of the equation $21-z=- 4;$

Step-by-step solution

Apply the concept of equation: 

An equation is a mathematical statement that two expressions are equal. The solution of an equation is the value that when substituted for the variable makes the equation a true statement.

Example: 3x + 5 = 14 is an equation, in which 3x+5 and 14 are two expressions separated by an ‘’equal’’ sign.

What are the steps to solve an equation? 

Step 1: Simplify each side of the equation by removing parenthesis and combining the like terms.

Step 2: Use addition or subtraction to isolate the variable term on one side (preferably in the left side).

Step 3: Use Multiplication or Division to solve for the variable.

Step 3: Tell whether the given value of the variable is a solution of the equation.21-z=-  4;  z=25

Solving the equation:

$\begin{array}{l}21-z=-4\\ 21-25=-4\\ -4=-4\end{array}$

Yes, the solution of the equation is $z=25$