Question

Difficulty: MediumEvaluating Algebraic Expressions

If x=−3x = -3, y=4y = 4, and z=−2z = -2, what is the value of the expression 2x2yz+5x\frac{2x^2y}{z} + 5x?

  1. A
    -87
  2. -51Answer
  3. C
    21
  4. D
    51

Answer

The evaluated result of the algebraic expression is -51.
The correct value is determined by carefully substituting the negative variables, properly applying the exponent to get a positive 99, calculating the fraction 72−2\frac{72}{-2} to get −36-36, and adding the −15-15 from the second term to reach −51-51.

Step-by-Step Solution

1
Substitute the given numerical values for each variable in the expression.
2(−3)2(4)−2+5(−3)\frac{2(-3)^2(4)}{-2} + 5(-3)
Variable substitution replaces letters with their specific numerical values to prepare for arithmetic calculation.
2
Evaluate the exponent according to the order of operations (PEMDAS).
(−3)2=9(-3)^2 = 9
Exponents must be calculated before multiplication or division.
3
Perform the multiplication in the numerator of the fraction and in the second term.
Numerator: 2(9)(4)=722(9)(4) = 72. Second term: 5(−3)=−155(-3) = -15. The expression is now 72−2+(−15)\frac{72}{-2} + (-15).
Multiplication is the next step in the order of operations.
4
Perform the division, then combine the remaining terms.
72−2=−36\frac{72}{-2} = -36. Finally, −36+(−15)=−51-36 + (-15) = -51.
Division occurs before addition, completing the evaluation.

Key Concept

Evaluating Algebraic Expressions
Estimated Time:1m 0s
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