Soru

Zorluk: KolayEvaluating Algebraic Expressions

Calculate the value of the algebraic expression x2−4yx^2 - 4y given that x=−5x = -5 and y=−2y = -2. What is the final value?

Cevap: 33

Cevap

33
By correctly applying substitution and the order of operations, squaring −5-5 gives 2525, and multiplying 44 by −2-2 gives −8-8. Subtracting −8-8 from 2525 results in 3333.

Adım Adım Çözüm

1
Substitute the given variable values into the expression
(−5)2−4(−2)(-5)^2 - 4(-2)
To replace the variables with their corresponding numerical values.
2
Evaluate the exponent
25−4(−2)25 - 4(-2)
Following the order of operations (PEMDAS), exponents must be calculated before multiplication and subtraction. The square of a negative number is positive.
3
Evaluate the multiplication
25−(−8)25 - (-8)
Multiply 4 by -2 to find the term to be subtracted.
4
Perform the final subtraction
25+8=3325 + 8 = 33
Subtracting a negative number is equivalent to adding its positive counterpart.

Anahtar Kavram

Evaluating Algebraic Expressions
Bu soruyu puanla