Soru

Zorluk: KolayBinary Operations

A binary operation \star is defined on the set of real numbers R\mathbb{R} by ab=a+b+7a \star b = a + b + 7. What is the identity element of the operation?

  1. 7-7Cevap
  2. B
    77
  3. C
    00
  4. D
    1-1

Cevap

The identity element of the operation is 7-7.
For an identity element ee, the condition ae=aa \star e = a must hold for all real numbers aa. Substituting the operation definition gives a+e+7=aa + e + 7 = a. Subtracting aa from both sides results in e+7=0e + 7 = 0, which solves to e=7e = -7.

Adım Adım Çözüm

1
Set up the defining equation for the identity element ee.
ae=aa \star e = a
By definition, an identity element ee leaves any element aa unchanged under the operation.
2
Apply the given rule for the binary operation.
a+e+7=aa + e + 7 = a
The binary operation is defined as ab=a+b+7a \star b = a + b + 7.
3
Solve for ee.
e=7e = -7
Subtracting a+7a + 7 from both sides gives e=7e = -7.

Anahtar Kavram

Identity element of a binary operation
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