Solve the following equations:
The problem presents four distinct, independent linear equations in the variable \(x\). Our goal is to solve for \(x\) in each individual case. Each equation is of the form \(ax + b = cx + d\), which we can solve by isolating the variable \(x\) using standard algebraic manipulations, such as performing the same arithmetic operation on both sides of the equation.
\(x = 7 - 3 = 4\).
\(x = 7 \times 3 = 21\).
\(3x = 13 - 1 = 12\).
Then, divide both sides by 3:
\(x = \frac{12}{3} = 4\).
\(10x - 4x - 15 = 27\), which simplifies to \(6x - 15 = 27\).
Next, add 15 to both sides to move the constant term:
\(6x = 27 + 15 = 42\).
Finally, divide by 6:
\(x = \frac{42}{6} = 7\).
By performing the required algebraic steps for each equation, we have determined the value of \(x\) for each case:
The solutions are \(\boxed{4, 21, 4, 7}\).
Solving linear equations is a fundamental skill used daily to manage resources or determine missing variables. For example, if you are saving money for a bicycle (x) and you currently have \(\$3\) saved and need \(\$7\) total, the equation \(x + 3 = 7\) models your situation. Similarly, if you want to distribute your total collection of marbles (\(x\)) into 3 groups and each group needs to have 7 marbles, \(\frac{x}{3} = 7\) helps you find your total collection size. Mastering these simple algebraic steps enables you to solve real-world problems involving balancing budgets, shopping, and planning.