Answer:

Step-by-step explanation:
Let's expand the expression bit by bit.
by FOIL.
We have that
.
So, the answer is 
Problem: You do not have an attached picture. Though, I can help you out with this question.
So, three-fifths of the members are girls. There are 30 of girls. We can immediately make an equation using "x".
3/5x=30
3/5x × 5/3=30 × 5/3
x=50
Thus, there are 50 members in total. Though if x is too hard for you, you may substitute it by using another variable.
Variable in here is x.
elimanation variations matrix
According to the question,
Let,
"n" represent the number of miles semir walked.
"y" represent the number of miles sarah walked.
Now, according to the question,
y = 2n - 5 ........................this is your equation
Also,
the question states, each of them collect $18 in pledges for every miles walked.
Given,
Sarah collected $450
Now,
Using unitary method,
Sarah collects $18 for 1 mile
Sarah collects $1 for (1 / $18) mile
Sarah collects $450 for (1 / 18) * 450 mile
= 25 miles
So, Sarah walks 25 miles.
Now,
Taking equation,
y = 2n - 5
Since, y is the no. of miles sarah walked, we can write 25 in place of "y" So,
(25) = 2n - 5
25 + 5 = 2n
30 = 2n
30 / 2 = n
15 = n
Since, "n" is the no. of miles that semir walked, Semir walked 15 miles.
2/5 is equivalent to 4/10 so at the end of February 4/10 was used up
And at the end of January, 3/10 was used
so 4/10 + 3/10 = 7/10
At the end of February, 7/10 of the wood was used