Solving 2x + 7 = 15

Pre-Algebra · Axiom Academy

EXAMPLE Solving Two-Step Equations Learn the correct order of operations when solving 2x + 7 = 15 . Solve the two-step equation 2x + 7 = 15 for x . We will isolate x by undoing each operation in reverse order — you decide the next move at every step. Great work! You've solved a two-step equation correctly. Remember: Work backwards from order of operations: to build 2x + 7 we first multiply by 2, then add 7 — so to undo it, reverse the order. Addition and subtraction first: undo the constant term before the coefficient. Whatever you do to one side, do to the other: this keeps the equation balanced. Always check your answer: substitute the solution back into the original equation to verify. Common mistake to avoid: don't divide by the coefficient before removing the constant term. This same method works for every two-step equation: undo the operations in reverse order from how they were applied.

This is the written version of the interactive lesson above. See the full Pre-Algebra course.