Mathematics
Grade 8
15 min
Evaluate nonlinear expressions
Evaluate nonlinear expressions
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1
Introduction & Learning Objectives
Learning Objectives
Identify variables, constants, and exponents within a nonlinear expression.
Substitute given numerical values for variables into nonlinear expressions.
Apply the order of operations (PEMDAS/BODMAS) correctly to evaluate nonlinear expressions.
Calculate the value of expressions involving exponents (squares and cubes).
Evaluate nonlinear expressions containing multiple operations and terms.
Distinguish between linear and nonlinear expressions based on the presence of exponents greater than one.
Ever wondered how engineers predict the strength of a bridge or how scientists model population growth? 🤔 It often involves understanding expressions that aren't just straight lines!
In this lesson, you'll learn how to find the numerical value of expressi...
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Key Concepts & Vocabulary
TermDefinitionExample
ExpressionA mathematical phrase that can contain numbers, variables, and operation symbols, but no equality sign.3x² + 5y - 7
VariableA symbol, usually a letter, that represents an unknown or changing quantity.In x² + 4, 'x' is the variable.
ConstantA number in an expression that has a fixed value and does not change.In 2x³ - 5, '-5' is the constant.
TermParts of an expression separated by addition or subtraction signs.In 4y² + 2y - 1, '4y²', '2y', and '-1' are terms.
Nonlinear ExpressionAn algebraic expression where at least one variable has an exponent greater than 1 (e.g., x², y³) or variables are multiplied together (e.g., xy).x² + 3x - 1 or 5ab
ExponentA number written above and to the right of a base number, ind...
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Core Formulas
Order of Operations (PEMDAS/BODMAS)
Parentheses/Brackets, Exponents/Orders, Multiplication and Division (from left to right), Addition and Subtraction (from left to right).
This rule ensures that everyone gets the same answer when evaluating an expression. Always perform operations in this specific order.
Substitution Principle
Replace each variable in an expression with its given numerical value.
Before performing any calculations, substitute the numbers for the letters. It's often helpful to use parentheses around the substituted values, especially for negative numbers.
Exponents Rule
$a^n = a \times a \times \dots \times a$ (n times)
An exponent tells you to multiply the base number by itself the number of times indicated by the exponent. For example, $x^2$ m...
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Challenging
Evaluate the expression 3(x² - 5)² when x = 2.
A.-3
B.3
C.9
D.-9
Challenging
Evaluate the expression a²b - ab² for a = -2 and b = 3.
A.-30
B.-6
C.6
D.30
Challenging
The value of the expression 3x² - 11 is 64. Which of the following is the correct positive value for x?
A.3
B.4
C.5
D.6
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