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Solve two-step equations

This understanding involves solving linear equations of forms such as ax+b=cax+b=c or x/a+b=cx/a+b=c, using inverse operations in a logically justified order while preserving equality and interpreting the variable as an unknown quantity. Solutions may involve rational numbers and are checked by substitution; the scope excludes equations requiring multiple additional transformations, variables on both sides, quadratics, and other more advanced algebraic cases.

Detailed Explanation: Solve two-step equations

A two-step equation has two operations acting on the variable. To solve it, undo those operations in reverse order while doing the same thing to both sides.

Example:

3x+5=203x+5=20

Step 1: Undo the addition.
Since 55 is added to 3x3x, subtract 55 from both sides:

3x+5−5=20−53x+5-5=20-5

Simplify:

3x=153x=15

Step 2: Undo the multiplication.
Since xx is multiplied by 33, divide both sides by 33:

3x3=153\frac{3x}{3}=\frac{15}{3}

Simplify:

x=5x=5

Check the solution by substituting 55 for xx in the original equation:

3(5)+5=15+5=203(5)+5=15+5=20

The statement is true, so the solution is:

x=5\boxed{x=5}

Learn by doing: Solve two-step equations

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Two-Step Equation - Subtraction and Multiplication - Solve


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