Answer:
C
Step-by-step explanation:
We know it's direct variation using the direct variation equation.
Where k is the constant.
Since 7 times x is the y values, 
Now we can substitute 7 into k of the direct variation equation.
Answer:
45,9
Step-by-step explanation:
Answer:
15x + 20y
Step-by-step explanation:
First, we need to combine like terms,
10x + 20y + 5x
15x + 20y
Since x and y are different variables, we cannot combine them, meaning that the answer is,
15x + 20y
Example :
x y
1 3
2 6
3 9
4 12
first thing u do is pick any 2 points (x,y) from ur table
(1,3) and (2,6)
now we sub those into the slope formula (y2 - y1) / (x2 - x1) to find the slope
(y2 - y1) / (x2 - x1)
(1,3)....x1 = 1 and y1 = 3
(2,6)...x2 = 2 and y2 = 6
sub
slope = (6 - 3) / (2 - 1) = 3/1 = 3
now we use slope intercept formula y = mx + b
y = mx + b
slope(m) = 3
use any point off ur table...(1,3)...x = 1 and y = 3
now we sub and find b, the y int
3 = 3(1) + b
3 = 3 + b
3 - 3 = b
0 = b
so ur equation is : y = 3x + 0....which can be written as y = 3x...and if u sub any of ur points into this equation, they should make the equation true....if they dont, then it is not correct
and if u need it in standard form..
y = 3x
-3x + y = 0
3x - y = 0 ...this is standard form
The Correct answer is
(n)(4) = (7)(8)
4n = 56
n = 14
