<u>Answer</u>:
x = 7, y = 2
<u>Explanation</u>:
equations given:
x + 7y = 21
x + 4y = 15
make "x" the subject:
x + 7y = 21
x = 21 - 7y .........equation 1
x + 4y = 15
x = 15 - 4y .......equation 2
Solving both the equations simultaneously:
15 - 4y = 21 - 7y
-4y + 7y = 21 - 15
3y = 6
y = 6 ÷ 3
y = 2
If y is 2
Then x = 21 -7y;
x = 21 - 7(2)
x = 21 - 14
x = 7
B) $8,250
explanation: since you have a total of 1800 sq ft and it’s $55 dollars per sq ft for the yr, you would start by finding how much it would cost for a year by taking $55 x 1800 sq ft= $99,000 then since you are trying to find the rent for a month you would take the yr value ($99,000) and divide it by 12 since there are 12 months in a yr
99,000/12 = $8,250

The account will have decreased by $2640 after 2/3 year.
Answer:
m=-9+n
Step-by-step explanation:
you want to get m by itself so you subtract 9 on both sides. 9-9 crosses out and you get m by itself. Which leads you to m= -9+n