Answer:
1. 7^(x-y)
2. z^5x^y
Step-by-step explanation:
The applicable rule of exponents is ...
(a^b)/(a^c) = a^(b-c)
__
1.

__
2.

Because 21 is more than 1
Answer:
x = -1, y = 1
Step-by-step explanation:
Given that:

Isolate x for 4x + 11y = 7 which ⇒ 
Substitute
into the equation: which is:

Drop Down to:

Isolate y for 7-8y = -1: y = 1
Thus, 
Substitute y = 1
Hence,

Solution ⇒ x = -1 and y = 1
<u><em>~learn with lenvy~</em></u>
When it is in () it means multiply x=45