Two-Step with Decimals
Part of the Fundamentals section of Coddy's Algebra journey. Lesson 42 of 64.
The equation 1.2x + 0.4 = 2.8 is a two-step equation with decimals. You solve it in the same order as before: subtract 0.4 from both sides, then divide both sides by 1.2.
1.2x = 2.4
x = 2
The decimals change the arithmetic, not the order of the steps. Check the answer: 1.2 × 2 + 0.4 = 2.8.
If you prefer whole numbers, multiply every term by 10 first. That gives 12x + 4 = 28, and you solve it with whole numbers. Multiplying by 10 clears a denominator of 10, because 1.2 = 12/10 and 0.4 = 4/10. Either way the equation has the same two steps: undo the added number, then undo the coefficient.
Challenge
MediumSolve the equation 1.5x - 0.5 = 4 for x.
Try it yourself
Solve for x
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Fundamentals
1What an Equation Is
The EquationFinding the UnknownThe Same to Both SidesSolved Means AloneRecap: First Equations4Two-Step Equations
Two Layers to UndoSubtract, Then DivideAdd, Then DivideA Division InsideNegatives in Two StepsRecap: Two-Step Equations2One-Step Equations
Undoing AdditionUndoing SubtractionUndoing MultiplicationUndoing DivisionInverse OperationsRecap: One-Step Equations5Tidying First
Like TermsTerms and Numbers MixedThe Distributive PropertyDistributing a SubtractionTidy, Then SolveRecap: Tidying First8Decimals and Percent
Decimal CoefficientsTwo-Step with DecimalsAdding a PercentPercent EquationsRecap: Decimals