Complete Guide Linear Equations
A linear equation is a statement that two linear expressions are equal. Your goal is to find the value of the variable that makes the statement true. This is called 'solving' the equation. This skill is critical for the SAT Math section.
1. Write Variable Equations: Word Problems
This is the most important skill: translating a story into a mathematical equation. Look for totals, and identify what the variable represents.
Example: Gym Membership
A gym charges a $50 sign-up fee and $35 per month. The total amount paid by a member was $400. Write an equation to find the number of months, m, the member has been at the gym.
2. Solve One-Step Linear Equations
To solve for a variable, you must isolate it. Use the inverse operation to "undo" the operation being performed on the variable. Addition undoes subtraction, and multiplication undoes division.
Example: Solve for x
x - 8 = 15
x =
4y = 28
y =
3. Solve One-Step Linear Equations: Word Problems
First, set up the equation from the word problem. Then, solve for the unknown variable.
Example: Savings Goal
Maria is saving for a new laptop that costs $520. She has already saved $150. How much more money, d, does she need to save? Set up and solve the equation.
150 + d = 520
d = $
Ready to Practice?
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Key Concepts: Flashcards
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Linear Equations: Practice Quiz
Answer the following questions to test your knowledge.