Answer
Find out the how many birds were at the shelter on Wednesday .
To prove
let us assume that the number of birds be = x
let us assume that the number of cats be = y
As given
An animal shelter spends $3.00 per day to care for each bird and $7.00 per day to care for each cat.
Alexandra noticed that the shelter spent $174.00 caring for birds and cats on Wednesday.
than the equation becomes
3x + 7y = 174
As given
Alexandra found a record showing that there were a total of 34 birds and cats on Wednesday.
than the equation becomes
x + y = 34
Than the two equation are
3x + 7y = 174
and x + y = 34
multiply 3 by x + y = 34 and subracted from 3x + 7y = 174
3x - 3x + 7y - 3y = 174 - 102
4y = 72
y = 18
put in the equation x + y = 34
18 + x = 34
x = 34 - 18
x = 16
The number of birds at the shelter on wednesday is 16 .