The correct answer is A.
You have direct variation if x and y are modeled by the equation

In this case, m is the constant of proportionality. So, if the constant has to be 2, the equation becomes

A side note: Actually, option C has a constant of proportionality of two as well, except the roles of x and y are interchanged. I chose option A because usually you want the y = mx form, but the names of the variables are obviously meaningless.
Answer: 10:7
Step-by-step explanation:
40:28=10*7
A. solve for 1 variable
let's solve for x in 2nd equation
add 2y to both sides
x=2y+4
sub 2y+4 for x in other equation
3(2y+4)+y=5
6y+12+y=5
7y+12=5
minu12 both sides
7y=-7
divide 7
y=-1
sub back
x=2y+4
x=2(-1)+4
x=-2+4
x=2
(2,-1)
B. eliminate
eliminate y's
multiply first equation by 2 and add to first
6x+2y=10
<u>x-2y=4 +</u>
7x+0y=14
7x=14
divide by 7
x=2
sub back
x-2y=4
2-2y=4
minus 2
-2y=2
divide -2
y=-1
(2,-1)
(2,-1) is answer
There ya go! The answer is 8 rows. Added a picture to show you my work :)
Answer:
m ∠S = 43°
Step-by-step explanation:
Exterior angle = Sum of opposite interior angles
(6x)° = 77° + (2x + 3)°
6x = 77 + 2x + 3
6x - 2x = 77 + 3
4x = 80
x = 20
m ∠S = (2x + 3)° = 2(20) + 3 = 40 + 3 = 43°