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 Single-variable equations Solve two-step linear equations It takes two steps to solve an equation that has two steps: Getting rid of the number "farthest" from the variable being solved. Eliminating the number "closest" to the variable. Solve for x: 2x+5=21 Notice that 2 is "closest" to variable x, and 5 is "farthest" away. This simple observation allows us to decide which number to eliminate first. It is obviously +5 because it is farther between the two. The opposite of +5 is -5, so that means we will subtract both sides of the equation by 5. 2x+5-5=21-5 2x=16 Now it's time to get rid of the number closest or directly attached to x which is 2. Since +2 is multiplying the variable x, its opposite operation is to divide by 2. $\fs2\;\frac{2x}{2}=\frac{16}{2}\;\;\Rightarrow\;x=8$