How to Do 9th Grade Algebra
Many states now require students to pass algebra exams in order to graduate, so if you are struggling in algebra, find a tutor or seek extra help from a teacher. Often a half-hour one-on-one session a few times per week can make the difference between a passing and failing grade. Here are outlined some of the most basic and important topics in a 9th grade algebra course. To understand these explanations, you'll need some familiarity with arithmetic operations and algebraic definitions. For example, you must know the algebraic meaning of the word "variable," which is an alphabetic letter representing a changing number.
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Instructions
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Expressions
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Learn the definitions of expressions and like terms. An expression is one or more terms separated by plus or minus signs, such as 5x^2 -- 4x + 3. Expressions do not have equal signs. Like terms are terms with the same variables and exponents. For instance, 5x and -2x are like terms, but 5x^2 and -2x are not like terms because they possess different exponents.
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Substitute a value for a variable, if such a value given in the problem. For example, say you're presented with the expression 3x -- 2 and told that x = 6. Replace the x in 3x -- 2 with the 6, yielding 3(6) -- 2. Simplify using the order of operations, also known as PEMDAS. Multiply 3 times 6 to get 18, then subtract 2 for an answer of 16.
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Simplify expressions for which no value for the variable is given. For instance, suppose you are asked to simplify the expression 9b + 7b^2 -- 4b -- 10b^2. Rewrite the expression in descending order, so that the like terms are next to each other, while preserving the plus or minus sign in front of each term. The above expression becomes -10b^2 + 7b^2 + 9b -- 4b. Combine only the like terms, yielding a solution of -3b^2 + 5b.
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Learn the definition of an equation. Equations consist of terms that show a relationship between one or more variables. Essentially, equations are just sets of expressions separated by equal signs, with one or more terms on both sides of the equal sign. An example of an equation is y = 8x + 3.
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Solve one-step addition and subtraction equations. For instance, consider the equation t -- 1 = 8. Add 1 to both sides to obtain a result of t = 9.
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Solve one-step multiplication and division equations. Take r/5 = 3, for instance. Multiply both sides by 5 to get a solution of r = 15.
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Solve multi-step equations by first using addition or subtraction and then using multiplication or division. For example, say you want to solve 3n + 5 = 17. Subtract 5 from both sides, obtaining 3n = 12. Then divide both sides by 3 for an answer of n = 4.
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