Answer:
D
Step-by-step explanation:
Using the sine ratio in the right triangle
sin B =
=
=
, thus
B =
(
) ≈ 12.84° → D
There are 3 ways of solving a simultaneous problem, substitution method, elimination method and Gauss-Jordan method. I'm gonna use the substitution method since it's easier and i think it would suit your level more.
First let's try solving for y since it's easier to start with.
Firstly we have to find an equation for x:

Great, now we can use the substitution method to find the value of y using the first equation:

Now we know that y=1 we can solve the first equation we made:

And the answer is 
Double check:

And that's our final answer! (4,1)
Answer:
click the button and use it as and use it
Answer:
angle C = 78
angle D = 108
Step-by-step explanation:
the measure of angle A is 102
To find the measure of angle C
let Angle C be x
102 + x = 180 (linear pair)
x = 180 -102
x = 78
angle C = 78
angle B = 78 (vertically opposite angles are equal)
angle D = 108 (vertically opposite angles are equal)
I think it would be C because the equation is y=7x. y=7x is also equal to x=1/7y. If y=45.50, then you would have to divide y by 7, which would equal 6.5.