Adding exponents

[Stockmoose16]

The MGMAT chapter on exponents says "you can never combine exponential equations linked by addition or subtraction.

So, for example:

2^7 + 3^7 CANNOT be combined, even though they have the same exponent. Then, in the very next chapter, it asks you to simplify the expression:

Root of x^2 y^3 + 3x^2 y^3

The answer states that one must simplify the root under the equation to:

4x^2 y^3

How is this possible? I thought you weren't allowed to add terms, even if they shared an exponent. And yet, that's exactly what they did. Please explain.

[sibbineni]

2^7 + 3^7 CANNOT be combined,

yes they cannot be combined .

you can add when you have numbers with same bases and same powers

ex:4^7+4^7==>2*4^7

even though they have the same exponent. Then, in the very next chapter, it asks you to simplify the expression:

Root of x^2 y^3 + 3x^2 y^3


here as the bases and powers are same they can be added--->

(or)
Root of x^2 y^3 + 3x^2 y^3
==>take out x^2y^3 as common then we have

===>Root of x^2 y^3 + 3x^2 y^3
===>Root ofx^2y^3(1+3)
===>Root of4x^2y^3