Answer:
Option A is correct.
Solution for the given equation is, 
Step-by-step explanation:
Given that : 
Let 
then our equation become;
.....[1]
A quadratic equation is of the form:
.....[2] where a, b and c are coefficient and the solution is given by;

Comparing equation [1] and [2] we get;
a = 2 b = -1 and c =-1
then;

Simplify:

or


or
and 
Simplify:
y = 1 and
Substitute y = cos x we have;

⇒
and

⇒
The solution set: 
Therefore, the solution for the given equation
is, 
I think isn't anyone of these alternatives because if we put number 15 in the place of y it is x-y=30. X-15=30
X=30+15=45.
X=45
Answer:
Step-by-step explanation:
115+94+107+2x=360 degree(sum of interior angles of four angles is always 360 degree)
316+2x=360
2x=360-316
x=44/2
x=22 degree
Answer:
2 kinds of shapes are used to create the faces on this three-dimensional model.