Numeric Substitutions:
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Evaluate 2x - 3, when x = 4. |
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Replace x with 4 and simplify. |
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2(4) - 3 = 8 - 3 = 5 Answer
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Evaluate x2 - 1, when x = 5. |
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Replace x with 5 and simplify. |
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(5)2 - 1 = 25 - 1 = 24 Answer
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Evaluate a2 + a, when a = 3. |
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Replace all values of a with 3 and simplify.
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(3)2 + (3) = 9 + 3 = 12 Answer
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Evaluate 6x + 3y, when x = 2 and y = 5. |
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Notice the use of two variables. Replace each and simplify. |
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6(2) + 3(5) = 12 + 15 = 27 Answer
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Evaluate x3 + 3x2 - 2x - 5, when x = -4. |
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Especially use parentheses when working with negative values. |
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(-4)3 + 3(-4)2 - 2(-4) - 5 = -64 + 48 + 8 - 5 = -13 Answer
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Evaluate a2b + a, when a = -3 and b = 2. |
Do NOT write:
-32(2) + (-3) as this is
-9(2) + (-3) = -21 |
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Parentheses are needed in this problem.
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(-3)2(2) + (-3) = 18 + (-3) = 15 Answer |
Algebraic Substitutions:
It may be the case that you will be asked to evaluate an expression using another expression.
Don't panic!!! Just follow the same process as you did when evaluating for a number.
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Evaluate x2 + 2x - 4, when x = 2a. |
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Remember to use parentheses! |
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(2a)2 + 2(2a) - 4 = 4a2 + 4a - 4 Answer
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