High School

Evaluate the expression:

\[ 125^{2/3} + 243^{2/5} - (-5) \times (-7) \]

A. -69
B. -1
C. -2
D. 1
E. 69

Answer :

To evaluate the expression [tex]125^{2/3} + 243^{2/5} - (-5) \times (-7)[/tex], we will solve it step-by-step.


  1. Evaluate [tex]125^{2/3}[/tex]:


    • [tex]125[/tex] is [tex]5^3[/tex] because [tex]5 \times 5 \times 5 = 125[/tex].

    • Therefore, [tex]125^{2/3} = (5^3)^{2/3} = 5^{(3 \times 2/3)} = 5^2 = 25[/tex].



  2. Evaluate [tex]243^{2/5}[/tex]:


    • [tex]243[/tex] is [tex]3^5[/tex] because [tex]3 \times 3 \times 3 \times 3 \times 3 = 243[/tex].

    • Therefore, [tex]243^{2/5} = (3^5)^{2/5} = 3^{(5 \times 2/5)} = 3^2 = 9[/tex].



  3. Evaluate [tex]-(-5) \times (-7)[/tex]:


    • The expression [tex](-5) \times (-7)[/tex] equals 35 because the product of two negative numbers is positive.



  4. Combine all parts together:


    • First, calculate [tex]125^{2/3} + 243^{2/5} = 25 + 9 = 34[/tex].

    • Then, calculate [tex]34 - 35 = -1[/tex].




Therefore, the value of the expression is -1.

The correct answer is option B: -1.