Question:
Evaluate the expression 5^x - 3^x for x=2
Answer:
5^x - 3^x for x=2 is 16
Step-by-step explanation:
Given
5^x - 3^x
x=2
Required
Evaluate
When fazed with question like this all you need is to substitute the value of x (or any other variable{s} used) in the expression.
Recall that x = 2
So, you have to substitute 2 for x in 5^x - 3^x
This gives
[tex]5^2 - 3^2[/tex]
This can be further solved in 2 ways
1. Solve directly
[tex]5^2 - 3^2[/tex]
= [tex]25 - 9[/tex]
= 16
2. Expand using difference of two squares.
Difference of two squares is represented by
[tex]a^2 - b^2 = (a + b) (a - b)[/tex]
By comparison
[tex]5^2 - 3^2[/tex] becomes
[tex]5^2 - 3^2 = (5 + 3) (5 - 3)[/tex]
[tex]5^2 - 3^2 = (8) (2)[/tex]
[tex]5^2 - 3^2 = 8 * 2[/tex]
[tex]5^2 - 3^2 = 16[/tex]
For both ways, we'll arrive at the same answer.
Hence, 5^x - 3^x for x=2 is 16
