Because both the x and y variables are associate with a value, you don’t just add 3x and 2x.
You have:
3x^5y^8 + 2x^5y^7
Apply the exponent rule a^b+c = a^ba^c
This means x^5y^8 = x^5y^7y
Now you have:
3x^5y^7y + 2x^5y^7
Since they both now have an x^5y^7 in them factor the out of both:
When you take that out it’d both numbers you are left with 3y + 2
The final answer is: X^5y^7(3y +2)
