Given:
Four equations in the options.
To find:
The equation which represents a proportional relationship.
Solution:
If y is proportional to x, then
where, k is the constant of proportionality.
In this case if x=0, then y=0. It means the graph of a proportional relationship passes through the origin.
From the given options, only option B, i.e., , is of the
, where,
.
So, the equation represents a proportional relationship.
Therefore, the correct option is B.
Answer:
y = and x =
Step-by-step explanation:
To solve simultaneous equations, you need to have the number in front of both x's or y's the same. (signs doesn't matter)
To get -x to -10x we simply need to multiply the first equation by 10:
-x * 10 = -10x
-9y * 10 = -90y
16 * 10 = 160
-10x - 90y = 160
Now we can add the two equations:
-10x + 10x = 0
-90y + 20y = -70y
160 + 20 = 180
-70y = 180
70y = -180
7y = -18
y =
Now plug into the second equation:
10x + 20() = 20
10x - = 20
Move the over to the other side, making it a positive:
10x = 20 +
10x =
Divide both sides by 10:
x =
So y = and x =
