Answer:
5390 gallons of water was wasted by the city's residents last year.
Step-by-step explanation:
Let
denotes gallons of water wasted by the city's residents last year.
Gallons of water wasted by the city's residents this year = 2695 gallons
This is 50% less than last year.
Therefore,

gallons
So, 5390 gallons of water was wasted by the city's residents last year.
Answer:
The system has infinite solutions
Step-by-step explanation:
For a system of two linear equations it is always true that if one equation is a linear combination of another, then the system will have infinite solutions.
Suppose we have the following system:

If there is a number n for which it is fulfilled that

Then the system has infinite solutions.
In this case the system is:

Observe that:

Then 
The system has infinite solutions
3.5 × 10 = 35.0
The mistake is that you only added a zero to the answer (3.5 -> 3.50), but you forgot to replace the point in your answer (because 3.50 is wrong and 35.0 is correct). Hence, you should have replaced to point, by moving it one spot to the right.
Answer:
$2,700
Step-by-step explanation:
Find the total donation amount by dividing 135 by 0.05:
135/0.05
= 2700
So, the class collected $2,700 in all
Answer:
3
Step-by-step explanation:
3x - ( x - 4 ) = 3x + 1
3x - x + 4 = 3x + 1
2x + 4 = 3x + 1
3x - 2x = 4 - 1
x = 3
Hope it will help :)