# Aptitude - Surds and Indices - Discussion

Discussion Forum : Surds and Indices - General Questions (Q.No. 1)
1.
(17)3.5 x (17)? = 178
2.29
2.75
4.25
4.5
Explanation:

Let (17)3.5 x (17)x = 178.

Then, (17)3.5 + x = 178.

3.5 + x = 8

x = (8 - 3.5)

x = 4.5

Discussion:
16 comments Page 1 of 2.

Glory said:   2 years ago
Thanks everyone.
(3)

Vijay said:   2 years ago
Yes, A^m * A^n = A^m+n.

Harry said:   6 years ago
Please explain the calculation of 17^3.5.

Rishikesh Agrawani said:   7 years ago
Just look at the below simple derivation.

a.a.a.......m times = a^m,
a.a.a.......n times. = a^n,
(a.a.a.......m times).(a.a.a.......n times) = a.a.a......m+n times = a^(m+n).

Now we got,
a^m . a^n = a^(m+n).
Applying the above formula to the given question,
17^3.5 . 17^x = 17^8,
17^(3.5+x) = 17^8,
3.5 + x = 8,
x = 4.5.
(2)

Y.mamaki said:   7 years ago
=17^3.5 * 17^*=17^8.
=17^3.5* * =17^8.
=17*= 17^8-3.5.
=17*= 4.5.

Ayovin said:   8 years ago
Simple 8 - 3.5 = 4.5.

Krishnalal Reang said:   9 years ago
I want with explanation and simple solution.

David wainaina said:   9 years ago
Simple maths you just do 8-3.5 = 4.5.

Taniya said:   10 years ago
@Mithun said the formula (x)y.(x)m = (x)y+m.

But in the second step when value are put then m is not write in the place after 17Ã-8 why?
(1)